给你一个简单的例子看看<html><head>
<script>
function js()
{
var a=document.getElementsByName("tt")
var give=0
for(i=0;i<a.length;i++)
{
give+=parseInt(a[i].value)
}
f1.sy.value=parseInt(f1.all.value)-give
if(give>f1.all.value){alert("所给分数大于总分")}
}
</script>
</head><body><form name="f1" method="POST" action="">
<p>
<input type="text" name="sy" size="6" disabled>剩余分数
<input type="text" name="all" size="6">总分</p>
<p><input type="text" name="tt" size="6" onkeyup="js()" value="0"></p>
<p><input type="text" name="tt" size="6" onkeyup="js()" value="0"></p>
<p><input type="text" name="tt" size="6" onkeyup="js()" value="0"></p>
<p><input type="text" name="tt" size="6" onkeyup="js()" value="0"></p>
<p><input type="text" name="tt" size="6" onkeyup="js()" value="0"></p>
<p><input type="button" value="提交" name="B1" onclick=""></p>
</form></body></html>
<script>
function js()
{
var a=document.getElementsByName("tt")
var give=0
for(i=0;i<a.length;i++)
{
give+=parseInt(a[i].value)
}
f1.sy.value=parseInt(f1.all.value)-give
if(give>f1.all.value){alert("所给分数大于总分")}
}
</script>
</head><body><form name="f1" method="POST" action="">
<p>
<input type="text" name="sy" size="6" disabled>剩余分数
<input type="text" name="all" size="6">总分</p>
<p><input type="text" name="tt" size="6" onkeyup="js()" value="0"></p>
<p><input type="text" name="tt" size="6" onkeyup="js()" value="0"></p>
<p><input type="text" name="tt" size="6" onkeyup="js()" value="0"></p>
<p><input type="text" name="tt" size="6" onkeyup="js()" value="0"></p>
<p><input type="text" name="tt" size="6" onkeyup="js()" value="0"></p>
<p><input type="button" value="提交" name="B1" onclick=""></p>
</form></body></html>
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<script>
function shownext(){
if(document.forms[0].aa.readOnly==false){
document.forms[0].aa.readOnly=true;
}
else{ document.forms[0].aa.readOnly=false;
document.forms[0].aa.value="现在可以填了!";
}
}
</script>
<form id=from>
<input type=checkbox onclick="shownext()">
<input type=text id=aa readonly=false value="不选前面的复选框,我不让你填">
</form>
________________________________________________________________________
测试通过
<input type="text" name="all" size="6">总分</p>
<div id=mydiv style="width:100px;height:30px;position:absolute;border:1px dotted #000000;display:none">
Content
</div>
<script>
function show()
{
var o=document.all.mydiv;
o.style.left=event.x;
o.style.top=event.y;
if(o.style.display=="block")
o.style.display="none";
else
o.style.display="block";
}
</script>