第1个回答 2014-10-31
<script type="text/javascript">
function sumnum(){
document.getElementById("sum").value=parseFloat(document.getElementById("sum").value)+parseFloat(document.getElementById("num").value);
}
</script>
<BODY>
<center>
<input type="text" id="num" onblur="sumnum();">
<input type="text" id="sum" value=0 >
</center>
</BODY>本回答被网友采纳