<form name=form1>
<input name=byear onblur="mm()">
<select name=type onchange="mm()">
<option value=17>初中
<option value=20 selected>高中
<option value=23>大专
<option value=24>大学
</select>
<input name=total>
</form>
<SCRIPT LANGUAGE="JavaScript">
function mm()
{
var t = document.form1.type.value;
var b = document.form1.byear.value;
if(b=="") return;
document.form1.total.value = parseInt(t)+parseInt(b);
}
</SCRIPT>
<input name=byear onblur="mm()">
<select name=type onchange="mm()">
<option value=17>初中
<option value=20 selected>高中
<option value=23>大专
<option value=24>大学
</select>
<input name=total>
</form>
<SCRIPT LANGUAGE="JavaScript">
function mm()
{
var t = document.form1.type.value;
var b = document.form1.byear.value;
if(b=="") return;
document.form1.total.value = parseInt(t)+parseInt(b);
}
</SCRIPT>
<input name=byear onblur="mm()" value="1980">
<select name=type onchange="mm()">
<option value="初中">初中
<option value="高中" selected>高中
<option value="大专">大专
<option value="大学">大学
</select>
<input name=total>
</form>
<SCRIPT LANGUAGE="JavaScript">
function mm()
{
var mm=
{
"初中" : 17,
"高中" : 20,
"大专" : 23,
"大学" : 24
}
var t = mm[document.form1.type.value];
var b = document.form1.byear.value;
if(b=="") return;
document.form1.total.value = parseInt(t)+parseInt(b);
}
</SCRIPT>