![](https://images2015.cnblogs.com/blog/990382/201701/990382-20170117150659286-1987069758.jpg)
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//HTML
<table border="1" width="100%" class="td-min-height">
<tbody>
<tr class="firstRow">
<td width="1373" valign="top">
<p>
value1:<input type="TEXT" title="DATA_58" size="40" name="DATA_58" onkeyup="enfocus()"/>
</p>
<p>
value2:<input type="TEXT" title="DATA_59" size="40" name="DATA_59" onkeyup="enfocus()"/>
</p>
<p>
相乘:<input type="TEXT" title="DATA_60" size="40" name="DATA_60" id="DATA_60"/><br/>
</p>
</td>
</tr>
</tbody>
</table>
<p>
<br/>
</p>
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//JS
function enfocus()
{
var t1 = document.forms[0].DATA_58.value;
var t2 = document.forms[0].DATA_59.value;
var t3 = document.forms[0].DATA_60.value ;
if(t1!="" && t2!=""){
document.getElementById("DATA_60").value = parseInt(t1) * parseInt(t2) ;
}
else {document.getElementById("DATA_60").value = "";}
}