js实现上传进度条

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML>
<HEAD>
<TITLE> New Document </TITLE>
<META NAME="Generator" CONTENT="EditPlus">
<META NAME="Author" CONTENT="">
<META NAME="Keywords" CONTENT="">
<META NAME="Description" CONTENT="">
<style type="text/css">
.spa{
font-size:12px;
color:#0066ff;

}
.put{
font-size:12px;
font-family:Arial;
color:#0066ff;
background-color:#fef4d9;
padding:0px;
border-style:none;
}

.put2{
font-size:12px;
color:#0066ff;
text-align:center;
border-width:medium;
border-style:none;
}

</style>
</HEAD>

<BODY>
<div >
<span class="spa">载入中,请稍等...</span>
<input readOnly />
<input readOnly />
</div>

<div >
<form name="upload" method="post" action="">
<input type="file" />
<input type="button" />
</form>
</div>
<script language="javascript">
var bar=0;
var line="||";
var amount="";
document.getElementById("up").style.display="none";
function count(){
var f = document.getElementById("f");
var b = document.getElementById("b");
b.disabled = true;
f.disabled = true;
if(f.value==""){
b.disabled = false;
f.disabled = false;
alert("请添加上传文件");
return false;
}
document.getElementById("up").style.display="inline";
bar = bar+2;
amount = amount+line;
document.getElementById("chart").value=amount;
document.getElementById("percent").value=bar+"%";
if(bar<99){
setTimeout("count()",200);
}else{
b.disabled = false;
f.disabled = false;
alert("加载完毕！");
document.getElementById("up").style.display="none";
// window.location="";
}
}

</script>
</BODY>
</HTML>