关于字符串的问题，请DX指教,谢谢！！

Question

if (s1.search(s2)!==-1) // !== ?if (s1.search(s2)!=-1)

Answer 1

试一试
<script language="javascript">
<!--
function checkupform()
{
for (var i=0;i<document.test.myselect.options.length;i++)
if (document.test.myselect.options[i].selected)
{
s1=document.test.mytext.value.tostring();
s2=document.test.myselect.options[i].value.tostring();
if (s1.search(s2)!==-1)
{
window.alert("该项已存在！");
}
}
-->
</script>

Answer 2

帮你测试通过了。
<form name="test">
<input type="text" name="mytext" value="abcdefg">
<select name="myselect" onchange="checkupform();">
<option value="abc">abc</option>
<option value="def">def</option>
<option value="ghi">ghi</option>
</select>
</form>
<script language="javascript">
<!--
function checkupform()
{
for (var i=0;i<test.myselect.options.length;i++)
if (test.myselect.options[i].selected)
{
var s1=document.test.mytext.value;
var s2=document.test.myselect.value;
if (s1.search(s2)!=-1)
{
window.alert("该项已存在！");
}
}
}
-->
</script>