342 lines
11 KiB
JavaScript
342 lines
11 KiB
JavaScript
/*! Respond.js v1.4.0: min/max-width media query polyfill. (c) Scott Jehl. MIT Lic. j.mp/respondjs */
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(function (w) {
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"use strict";
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//exposed namespace
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var respond = {};
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w.respond = respond;
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//define update even in native-mq-supporting browsers, to avoid errors
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respond.update = function () { };
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//define ajax obj
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var requestQueue = [],
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xmlHttp = (function () {
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var xmlhttpmethod = false;
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try {
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xmlhttpmethod = new w.XMLHttpRequest();
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}
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catch (e) {
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xmlhttpmethod = new w.ActiveXObject("Microsoft.XMLHTTP");
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}
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return function () {
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return xmlhttpmethod;
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};
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})(),
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//tweaked Ajax functions from Quirksmode
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ajax = function (url, callback) {
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var req = xmlHttp();
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if (!req) {
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return;
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}
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req.open("GET", url, true);
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req.onreadystatechange = function () {
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if (req.readyState !== 4 || req.status !== 200 && req.status !== 304) {
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return;
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}
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callback(req.responseText);
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};
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if (req.readyState === 4) {
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return;
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}
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req.send(null);
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};
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//expose for testing
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respond.ajax = ajax;
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respond.queue = requestQueue;
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// expose for testing
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respond.regex = {
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media: /@media[^\{]+\{([^\{\}]*\{[^\}\{]*\})+/gi,
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keyframes: /@(?:\-(?:o|moz|webkit)\-)?keyframes[^\{]+\{(?:[^\{\}]*\{[^\}\{]*\})+[^\}]*\}/gi,
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urls: /(url\()['"]?([^\/\)'"][^:\)'"]+)['"]?(\))/g,
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findStyles: /@media *([^\{]+)\{([\S\s]+?)$/,
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only: /(only\s+)?([a-zA-Z]+)\s?/,
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minw: /\([\s]*min\-width\s*:[\s]*([\s]*[0-9\.]+)(px|em)[\s]*\)/,
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maxw: /\([\s]*max\-width\s*:[\s]*([\s]*[0-9\.]+)(px|em)[\s]*\)/
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};
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//expose media query support flag for external use
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respond.mediaQueriesSupported = w.matchMedia && w.matchMedia("only all") !== null && w.matchMedia("only all").matches;
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//if media queries are supported, exit here
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if (respond.mediaQueriesSupported) {
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return;
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}
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//define vars
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var doc = w.document,
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docElem = doc.documentElement,
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mediastyles = [],
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rules = [],
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appendedEls = [],
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parsedSheets = {},
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resizeThrottle = 30,
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head = doc.getElementsByTagName("head")[0] || docElem,
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base = doc.getElementsByTagName("base")[0],
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links = head.getElementsByTagName("link"),
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lastCall,
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resizeDefer,
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//cached container for 1em value, populated the first time it's needed
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eminpx,
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// returns the value of 1em in pixels
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getEmValue = function () {
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var ret,
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div = doc.createElement('div'),
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body = doc.body,
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originalHTMLFontSize = docElem.style.fontSize,
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originalBodyFontSize = body && body.style.fontSize,
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fakeUsed = false;
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div.style.cssText = "position:absolute;font-size:1em;width:1em";
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if (!body) {
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body = fakeUsed = doc.createElement("body");
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body.style.background = "none";
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}
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// 1em in a media query is the value of the default font size of the browser
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// reset docElem and body to ensure the correct value is returned
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docElem.style.fontSize = "100%";
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body.style.fontSize = "100%";
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body.appendChild(div);
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if (fakeUsed) {
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docElem.insertBefore(body, docElem.firstChild);
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}
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ret = div.offsetWidth;
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if (fakeUsed) {
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docElem.removeChild(body);
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}
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else {
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body.removeChild(div);
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}
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// restore the original values
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docElem.style.fontSize = originalHTMLFontSize;
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if (originalBodyFontSize) {
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body.style.fontSize = originalBodyFontSize;
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}
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//also update eminpx before returning
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ret = eminpx = parseFloat(ret);
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return ret;
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},
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//enable/disable styles
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applyMedia = function (fromResize) {
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var name = "clientWidth",
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docElemProp = docElem[name],
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currWidth = doc.compatMode === "CSS1Compat" && docElemProp || doc.body[name] || docElemProp,
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styleBlocks = {},
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lastLink = links[links.length - 1],
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now = (new Date()).getTime();
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//throttle resize calls
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if (fromResize && lastCall && now - lastCall < resizeThrottle) {
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w.clearTimeout(resizeDefer);
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resizeDefer = w.setTimeout(applyMedia, resizeThrottle);
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return;
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}
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else {
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lastCall = now;
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}
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for (var i in mediastyles) {
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if (mediastyles.hasOwnProperty(i)) {
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var thisstyle = mediastyles[i],
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min = thisstyle.minw,
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max = thisstyle.maxw,
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minnull = min === null,
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maxnull = max === null,
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em = "em";
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if (!!min) {
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min = parseFloat(min) * (min.indexOf(em) > -1 ? (eminpx || getEmValue()) : 1);
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}
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if (!!max) {
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max = parseFloat(max) * (max.indexOf(em) > -1 ? (eminpx || getEmValue()) : 1);
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}
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// if there's no media query at all (the () part), or min or max is not null, and if either is present, they're true
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if (!thisstyle.hasquery || (!minnull || !maxnull) && (minnull || currWidth >= min) && (maxnull || currWidth <= max)) {
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if (!styleBlocks[thisstyle.media]) {
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styleBlocks[thisstyle.media] = [];
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}
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styleBlocks[thisstyle.media].push(rules[thisstyle.rules]);
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}
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}
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}
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//remove any existing respond style element(s)
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for (var j in appendedEls) {
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if (appendedEls.hasOwnProperty(j)) {
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if (appendedEls[j] && appendedEls[j].parentNode === head) {
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head.removeChild(appendedEls[j]);
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}
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}
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}
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appendedEls.length = 0;
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//inject active styles, grouped by media type
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for (var k in styleBlocks) {
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if (styleBlocks.hasOwnProperty(k)) {
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var ss = doc.createElement("style"),
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css = styleBlocks[k].join("\n");
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ss.type = "text/css";
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ss.media = k;
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//originally, ss was appended to a documentFragment and sheets were appended in bulk.
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//this caused crashes in IE in a number of circumstances, such as when the HTML element had a bg image set, so appending beforehand seems best. Thanks to @dvelyk for the initial research on this one!
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head.insertBefore(ss, lastLink.nextSibling);
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if (ss.styleSheet) {
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ss.styleSheet.cssText = css;
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}
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else {
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ss.appendChild(doc.createTextNode(css));
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}
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//push to appendedEls to track for later removal
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appendedEls.push(ss);
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}
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}
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},
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//find media blocks in css text, convert to style blocks
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translate = function (styles, href, media) {
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var qs = styles.replace(respond.regex.keyframes, '').match(respond.regex.media),
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ql = qs && qs.length || 0;
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//try to get CSS path
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href = href.substring(0, href.lastIndexOf("/"));
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var repUrls = function (css) {
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return css.replace(respond.regex.urls, "$1" + href + "$2$3");
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},
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useMedia = !ql && media;
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//if path exists, tack on trailing slash
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if (href.length) { href += "/"; }
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//if no internal queries exist, but media attr does, use that
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//note: this currently lacks support for situations where a media attr is specified on a link AND
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//its associated stylesheet has internal CSS media queries.
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//In those cases, the media attribute will currently be ignored.
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if (useMedia) {
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ql = 1;
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}
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for (var i = 0; i < ql; i++) {
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var fullq, thisq, eachq, eql;
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//media attr
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if (useMedia) {
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fullq = media;
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rules.push(repUrls(styles));
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}
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//parse for styles
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else {
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fullq = qs[i].match(respond.regex.findStyles) && RegExp.$1;
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rules.push(RegExp.$2 && repUrls(RegExp.$2));
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}
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eachq = fullq.split(",");
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eql = eachq.length;
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for (var j = 0; j < eql; j++) {
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thisq = eachq[j];
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mediastyles.push({
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media: thisq.split("(")[0].match(respond.regex.only) && RegExp.$2 || "all",
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rules: rules.length - 1,
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hasquery: thisq.indexOf("(") > -1,
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minw: thisq.match(respond.regex.minw) && parseFloat(RegExp.$1) + (RegExp.$2 || ""),
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maxw: thisq.match(respond.regex.maxw) && parseFloat(RegExp.$1) + (RegExp.$2 || "")
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});
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}
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}
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applyMedia();
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},
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//recurse through request queue, get css text
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makeRequests = function () {
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if (requestQueue.length) {
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var thisRequest = requestQueue.shift();
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ajax(thisRequest.href, function (styles) {
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translate(styles, thisRequest.href, thisRequest.media);
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parsedSheets[thisRequest.href] = true;
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// by wrapping recursive function call in setTimeout
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// we prevent "Stack overflow" error in IE7
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w.setTimeout(function () { makeRequests(); }, 0);
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});
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}
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},
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//loop stylesheets, send text content to translate
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ripCSS = function () {
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for (var i = 0; i < links.length; i++) {
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var sheet = links[i],
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href = sheet.href,
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media = sheet.media,
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isCSS = sheet.rel && sheet.rel.toLowerCase() === "stylesheet";
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//only links plz and prevent re-parsing
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if (!!href && isCSS && !parsedSheets[href]) {
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// selectivizr exposes css through the rawCssText expando
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if (sheet.styleSheet && sheet.styleSheet.rawCssText) {
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translate(sheet.styleSheet.rawCssText, href, media);
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parsedSheets[href] = true;
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} else {
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if ((!/^([a-zA-Z:]*\/\/)/.test(href) && !base) ||
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href.replace(RegExp.$1, "").split("/")[0] === w.location.host) {
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// IE7 doesn't handle urls that start with '//' for ajax request
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// manually add in the protocol
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if (href.substring(0, 2) === "//") { href = w.location.protocol + href; }
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requestQueue.push({
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href: href,
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media: media
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});
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}
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}
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}
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}
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makeRequests();
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};
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//translate CSS
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ripCSS();
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//expose update for re-running respond later on
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respond.update = ripCSS;
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//expose getEmValue
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respond.getEmValue = getEmValue;
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//adjust on resize
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function callMedia() {
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applyMedia(true);
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}
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if (w.addEventListener) {
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w.addEventListener("resize", callMedia, false);
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}
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else if (w.attachEvent) {
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w.attachEvent("onresize", callMedia);
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}
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})(this);
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