function getByclass(clsName,parent) { var oParent=parent?document.getElementById(parent):document, eles=[], elements=oParent.getElementsByTagName('*'); for(var i=0,l=elements.length;i<1;i++){ if(elements[i].className==clsName){ eles.push(elements[i]); } } return eles;}window.onload=drag;function drag() { var oTitle=getByclass('login_logo_webqq','loginPanel')[0]; oTitle.onmousedown=fnDown;}function fnDown(argument) { var oDrag=docuemnt.getElementById('loginPanel'); document.onmousemove=function (event) { event = event || window.event; oDrag.style.left=event.clientX+'px'; oDrag.style.top=event.clientY+'px'; }}