JavaScript动态创建预览网页

//创建一个预览框
var newElement = document.createElement('iframe');
newElement.id = yulanid.replace(/btyl/,"ylDiv");
newElement.src = URL;
newElement.name = 'ylframe';
newElement.width = '800';
newElement.height = '600';
newElement.marginwidth = '5';
newElement.marginheight = '5';
newElement.frameborder = 1;
newElement.scrolling = "yes";
buttonform.insertBefore(newElement,button);