帮我看这段程序为什么运行没效果?
<html>
<head>
<title> mofile to tqcity </title>
<meta http-equiv= "Cache-Control " content= "no-cache ">
<meta http-equiv= "Content-Type " content= "text/html; charset=UTF-8 " />
<script type= "text/javascript " src= "prototype.js "> </script>
</head>
<body>
<script charset= "gb2312 ">
function format(){
ob.InnerHtmL= "abc ";
}
</script>
</body>
<form>
<input id= "source " type= "text ">
<input type= "button " value= "转换 " onclick= "format(); ">
<div id= "ob ">
</div>
</form>
</html>
------解决方案--------------------document.getElementById( "ob ").innerHTML= '123 '
document.getElementById( "ob ").innerText= '123 '