function createScript(src,callback,tag){
	var oScript = document.createElement('script');
	oScript.setAttribute('type','text/javascript');
	oScript.src = src;
	if(typeof tag != 'undefined')
		oScript.setAttribute('tag',tag);
	oScript[document.all?"onreadystatechange":"onload"]=function(){
		if(typeof callback=='function')
			callback();
    }
	document.getElementsByTagName('head')[0].appendChild(oScript);
}