getelementsbyclassname[收藏好代码]

/*Developed by Robert Nyman, http://www.robertnyman.comCode/licensing: http://code.google.com/p/getelementsbyclassname/*/var getElementsByClassName = function (className, tag, elm){if (document.getElementsByClassName) {getElementsByClassName = function (className, tag, elm) {elm = elm || document;var elements = elm.getElementsByClassName(className),nodeName = (tag)? new RegExp("\\b" + tag + "\\b", "i") : null,returnElements = [],current;for(var i=0, il=elements.length; i<il; i+=1){current = elements[i];if(!nodeName || nodeName.test(current.nodeName)) {returnElements.push(current);}}return returnElements;};}else if (document.evaluate) {getElementsByClassName = function (className, tag, elm) {tag = tag || "*";elm = elm || document;var classes = className.split(" "),classesToCheck = "",xhtmlNamespace = "http://www.w3.org/1999/xhtml",namespaceResolver = (document.documentElement.namespaceURI === xhtmlNamespace)? xhtmlNamespace : null,returnElements = [],elements,node;for(var j=0, jl=classes.length; j<jl; j+=1){classesToCheck += "[contains(concat(' ', @class, ' '), ' " + classes[j] + " ')]";}try{elements = document.evaluate(".//" + tag + classesToCheck, elm, namespaceResolver, 0, null);}catch (e) {elements = document.evaluate(".//" + tag + classesToCheck, elm, null, 0, null);}while ((node = elements.iterateNext())) {returnElements.push(node);}return returnElements;};}else {getElementsByClassName = function (className, tag, elm) {tag = tag || "*";elm = elm || document;var classes = className.split(" "),classesToCheck = [],elements = (tag === "*" && elm.all)? elm.all : elm.getElementsByTagName(tag),current,returnElements = [],match;for(var k=0, kl=classes.length; k<kl; k+=1){classesToCheck.push(new RegExp("(^|\\s)" + classes[k] + "(\\s|$)"));}for(var l=0, ll=elements.length; l<ll; l+=1){current = elements[l];match = false;for(var m=0, ml=classesToCheck.length; m<ml; m+=1){match = classesToCheck[m].test(current.className);if (!match) {break;}}if (match) {returnElements.push(current);}}return returnElements;};}return getElementsByClassName(className, tag, elm);};