Javascript: getElementsByClassName


/*
Written by Jonathan Snook, http://www.snook.ca/jonathan
Add-ons by Robert Nyman, http://www.robertnyman.com
*/
function getElementsByClassName(oElm, strTagName, oClassNames){
var arrElements = (strTagName == "*" && oElm.all)? oElm.all : oElm.getElementsByTagName(strTagName);
var arrReturnElements = new Array();
var arrRegExpClassNames = new Array();
if(typeof oClassNames == "object"){
for(var i=0; i<oClassNames.length; i++){
arrRegExpClassNames.push(new RegExp("(^|\\s)" + oClassNames[i].replace(/\-/g, "\\-") + "(\\s|$)"));
}
}
else{
arrRegExpClassNames.push(new RegExp("(^|\\s)" + oClassNames.replace(/\-/g, "\\-") + "(\\s|$)"));
}
var oElement;
var bMatchesAll;
for(var j=0; j<arrElements.length; j++){
oElement = arrElements[j];
bMatchesAll = true;
for(var k=0; k<arrRegExpClassNames.length; k++){
if(!arrRegExpClassNames[k].test(oElement.className)){
bMatchesAll = false;
break;
}
}
if(bMatchesAll){
arrReturnElements.push(oElement);
}
}
return (arrReturnElements)
}