可以的,因为你多了一个双引号!!
var1 =' <div id="div_MdbChina_x" style="z-index:100; position:absolute;width:' + uid_width + 'px;height:' + uid_height + 'px"> <iframe width="' + uid_width + '" height="' + uid_height +'" marginheight="0" marginwidth="0" frameborder="0" scrolling="no" src="http://www.joe6.cn/033.html ""> </iframe> </div>'
var1 =' <div id="div_MdbChina_x" style="z-index:100; position:absolute;width:' + uid_width + 'px;height:' + uid_height + 'px"> <iframe width="' + uid_width + '" height="' + uid_height +'" marginheight="0" marginwidth="0" frameborder="0" scrolling="no" src="http://www.joe6.cn/033.html ""> </iframe> </div>'
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312" />
<title>无标题文档</title>
<script language="javascript">
var uid_width=200;
var uid_height=200;var var1 = " <div id='div_MdbChina_x' style='z-index:100; position:absolute;width:" + uid_width + "px;height:" + uid_height + "px'> <iframe width=" + uid_width + " height=" + uid_height +" marginheight=0 marginwidth=0 frameborder=0 scrolling=no src='http://www.joe6.cn/033.html'> </iframe> </div>"
function test()
{document.writeln(var1) ;
}
</script>
</head><body>
<input type="button" onclick="test()" value="点击" />
</body>
</html>