$(window.parent.document).find("#folder_12").click();

<a id="folder_14" onClick="changeContent('classManager/classList.do',this);" onFocus="this.blur()" href="javascript:void(0);" target="mainFrame">班級管理</a>

//console.info( $(window.parent.document).find("a") );
$(window.parent.document).find("#OutFolder a").each(function (index, domEle) {
//var s = $(domEle).attr("onclick")+"";
//var start = s.indexOf ('classManager/classList.do');
var str = domEle.attributes.onclick.value;//利用js獲取onclick屬性值，搜索url
var start = str.indexOf ('classManager/classList.do');
if(start>0){
$(domEle).click();
}
});