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Utensil's technical posts in Chinese (mostly 2005-2020) utensil.tngl.sh/tech
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13 kB · 343 lines
JavaScript
at middleman
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window.matchMedia = window.matchMedia || (function( doc, undefined ) {
"use strict";
var bool, docElem = doc.documentElement, refNode = docElem.firstElementChild || docElem.firstChild, // fakeBody required for <FF4 when executed in <head> fakeBody = doc.createElement( "body" ), div = doc.createElement( "div" );
div.id = "mq-test-1"; div.style.cssText = "position:absolute;top:-100em"; fakeBody.style.background = "none"; fakeBody.appendChild(div);
return function(q){
div.innerHTML = "­<style media=\"" + q + "\"> #mq-test-1 { width: 42px; }</style>";
docElem.insertBefore( fakeBody, refNode ); bool = div.offsetWidth === 42; docElem.removeChild( fakeBody );
return { matches: bool, media: q };
};
}( document ));
/*! Respond.js v1.1.0: min/max-width media query polyfill. (c) Scott Jehl. MIT/GPLv2 Lic. j.mp/respondjs */(function( win ){
"use strict";
//exposed namespace var respond = {}; win.respond = respond; //define update even in native-mq-supporting browsers, to avoid errors respond.update = function(){}; //expose media query support flag for external use respond.mediaQueriesSupported = win.matchMedia && win.matchMedia( "only all" ).matches; //if media queries are supported, exit here if( respond.mediaQueriesSupported ){ return; } //define vars var doc = win.document, docElem = doc.documentElement, mediastyles = [], rules = [], appendedEls = [], parsedSheets = {}, resizeThrottle = 30, head = doc.getElementsByTagName( "head" )[0] || docElem, base = doc.getElementsByTagName( "base" )[0], links = head.getElementsByTagName( "link" ), requestQueue = [], //loop stylesheets, send text content to translate ripCSS = function(){
for( var i = 0; i < links.length; i++ ){ var sheet = links[ i ], href = sheet.href, media = sheet.media, isCSS = sheet.rel && sheet.rel.toLowerCase() === "stylesheet";
//only links plz and prevent re-parsing if( !!href && isCSS && !parsedSheets[ href ] ){ // selectivizr exposes css through the rawCssText expando if (sheet.styleSheet && sheet.styleSheet.rawCssText) { translate( sheet.styleSheet.rawCssText, href, media ); parsedSheets[ href ] = true; } else { if( (!/^([a-zA-Z:]*\/\/)/.test( href ) && !base) || href.replace( RegExp.$1, "" ).split( "/" )[0] === win.location.host ){ requestQueue.push( { href: href, media: media } ); } } } } makeRequests(); }, //recurse through request queue, get css text makeRequests = function(){ if( requestQueue.length ){ var thisRequest = requestQueue.shift(); ajax( thisRequest.href, function( styles ){ translate( styles, thisRequest.href, thisRequest.media ); parsedSheets[ thisRequest.href ] = true;
// by wrapping recursive function call in setTimeout // we prevent "Stack overflow" error in IE7 win.setTimeout(function(){ makeRequests(); },0); } ); } }, //find media blocks in css text, convert to style blocks translate = function( styles, href, media ){ var qs = styles.match( /@media[^\{]+\{([^\{\}]*\{[^\}\{]*\})+/gi ), ql = qs && qs.length || 0;
//try to get CSS path href = href.substring( 0, href.lastIndexOf( "/" ) );
var repUrls = function( css ){ return css.replace( /(url\()['"]?([^\/\)'"][^:\)'"]+)['"]?(\))/g, "$1" + href + "$2$3" ); }, useMedia = !ql && media;
//if path exists, tack on trailing slash if( href.length ){ href += "/"; } //if no internal queries exist, but media attr does, use that //note: this currently lacks support for situations where a media attr is specified on a link AND //its associated stylesheet has internal CSS media queries. //In those cases, the media attribute will currently be ignored. if( useMedia ){ ql = 1; }
for( var i = 0; i < ql; i++ ){ var fullq, thisq, eachq, eql;
//media attr if( useMedia ){ fullq = media; rules.push( repUrls( styles ) ); } //parse for styles else{ fullq = qs[ i ].match( /@media *([^\{]+)\{([\S\s]+?)$/ ) && RegExp.$1; rules.push( RegExp.$2 && repUrls( RegExp.$2 ) ); } eachq = fullq.split( "," ); eql = eachq.length; for( var j = 0; j < eql; j++ ){ thisq = eachq[ j ]; mediastyles.push( { media : thisq.split( "(" )[ 0 ].match( /(only\s+)?([a-zA-Z]+)\s?/ ) && RegExp.$2 || "all", rules : rules.length - 1, hasquery : thisq.indexOf("(") > -1, minw : thisq.match( /\(\s*min\-width\s*:\s*(\s*[0-9\.]+)(px|em)\s*\)/ ) && parseFloat( RegExp.$1 ) + ( RegExp.$2 || "" ), maxw : thisq.match( /\(\s*max\-width\s*:\s*(\s*[0-9\.]+)(px|em)\s*\)/ ) && parseFloat( RegExp.$1 ) + ( RegExp.$2 || "" ) } ); } }
applyMedia(); }, lastCall, resizeDefer, // returns the value of 1em in pixels getEmValue = function() { var ret, div = doc.createElement('div'), body = doc.body, fakeUsed = false; div.style.cssText = "position:absolute;font-size:1em;width:1em"; if( !body ){ body = fakeUsed = doc.createElement( "body" ); body.style.background = "none"; } body.appendChild( div ); docElem.insertBefore( body, docElem.firstChild ); ret = div.offsetWidth; if( fakeUsed ){ docElem.removeChild( body ); } else { body.removeChild( div ); } //also update eminpx before returning ret = eminpx = parseFloat(ret); return ret; }, //cached container for 1em value, populated the first time it's needed eminpx, //enable/disable styles applyMedia = function( fromResize ){ var name = "clientWidth", docElemProp = docElem[ name ], currWidth = doc.compatMode === "CSS1Compat" && docElemProp || doc.body[ name ] || docElemProp, styleBlocks = {}, lastLink = links[ links.length-1 ], now = (new Date()).getTime();
//throttle resize calls if( fromResize && lastCall && now - lastCall < resizeThrottle ){ win.clearTimeout( resizeDefer ); resizeDefer = win.setTimeout( applyMedia, resizeThrottle ); return; } else { lastCall = now; } for( var i in mediastyles ){ if( mediastyles.hasOwnProperty( i ) ){ var thisstyle = mediastyles[ i ], min = thisstyle.minw, max = thisstyle.maxw, minnull = min === null, maxnull = max === null, em = "em"; if( !!min ){ min = parseFloat( min ) * ( min.indexOf( em ) > -1 ? ( eminpx || getEmValue() ) : 1 ); } if( !!max ){ max = parseFloat( max ) * ( max.indexOf( em ) > -1 ? ( eminpx || getEmValue() ) : 1 ); } // 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 if( !thisstyle.hasquery || ( !minnull || !maxnull ) && ( minnull || currWidth >= min ) && ( maxnull || currWidth <= max ) ){ if( !styleBlocks[ thisstyle.media ] ){ styleBlocks[ thisstyle.media ] = []; } styleBlocks[ thisstyle.media ].push( rules[ thisstyle.rules ] ); } } } //remove any existing respond style element(s) for( var j in appendedEls ){ if( appendedEls.hasOwnProperty( j ) ){ if( appendedEls[ j ] && appendedEls[ j ].parentNode === head ){ head.removeChild( appendedEls[ j ] ); } } } //inject active styles, grouped by media type for( var k in styleBlocks ){ if( styleBlocks.hasOwnProperty( k ) ){ var ss = doc.createElement( "style" ), css = styleBlocks[ k ].join( "\n" ); ss.type = "text/css"; ss.media = k; //originally, ss was appended to a documentFragment and sheets were appended in bulk. //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! head.insertBefore( ss, lastLink.nextSibling ); if ( ss.styleSheet ){ ss.styleSheet.cssText = css; } else { ss.appendChild( doc.createTextNode( css ) ); }
//push to appendedEls to track for later removal appendedEls.push( ss ); } } }, //tweaked Ajax functions from Quirksmode ajax = function( url, callback ) { var req = xmlHttp(); if (!req){ return; } req.open( "GET", url, true ); req.onreadystatechange = function () { if ( req.readyState !== 4 || req.status !== 200 && req.status !== 304 ){ return; } callback( req.responseText ); }; if ( req.readyState === 4 ){ return; } req.send( null ); }, //define ajax obj xmlHttp = (function() { var xmlhttpmethod = false; try { xmlhttpmethod = new win.XMLHttpRequest(); } catch( e ){ xmlhttpmethod = new win.ActiveXObject( "Microsoft.XMLHTTP" ); } return function(){ return xmlhttpmethod; }; })(); //translate CSS ripCSS(); //expose update for re-running respond later on respond.update = ripCSS; //adjust on resize function callMedia(){ applyMedia( true ); } if( win.addEventListener ){ win.addEventListener( "resize", callMedia, false ); } else if( win.attachEvent ){ win.attachEvent( "onresize", callMedia ); }})(this);