åè代ç å¦ä¸ï¼
<script>
function a(){
var slt=document.getElementById("abc");âåå¾æ ç¾select
if(slt.value==""){ 'å¤ææ¯å¦éä¸
alert("éæ©ä¸é¡¹");
return false;
}
return true;
}
</script>
<form method=post onsubmit=" return a()">
<select id="abc">
<option value="">éä¸é¡¹</option>
<option value="x">A</option>
<option value="z">B</option>
</select>
<input type=submit value="æ交">
</form>
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