3个下拉菜单如何验证是否选项有重复
3个下拉菜单怎么验证是否选项有重复
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>无标题文档</title>
<script language="javaScript">
function check()
{
var lm = document.form1.lm.value;
var lm1 = document.form1.lm1.value;
var lm2 = document.form1.lm2.value;
if((lm==lm1||lm==lm2||lm1==lm2)&&(lm1!=0&&lm!=0&&lm2!=0))
{
alert('该栏目已选择');
return false;
}
{
return true;
}
}
</script>
</head>
<body>
<form name="form1" method="post" action="addnewt.asp" onsubmit="return check()" >
<select name="lm" style="width:120px;" ID="lm" >
<option value="0" selected="true">——请选择——</option>
<option value="1" >1</option>
<option value="2">2</option>
<option value="3">3</option>
<option value="4">4</option>
<option value="5">5</option>
<option value="6">6</option>
<option value="7">7</option>
<option value="8">8</option>
</select>
<input type="button" name="btn" onclick="hidslt()" value=增加第二栏目 >
<select name="lm1" style="width:120px; display:none" ID="lm1" >
<option value="0" selected="true">——请选择——</option>
<option value="1" >1</option>
<option value="2">2</option>
<option value="3">3</option>
<option value="4">4</option>
<option value="5">5</option>
<option value="6">6</option>
<option value="7">7</option>
<option value="8">8</option>
</select>
<input type="button" name="btn1" onclick="hidslt1()" value="增加第三栏目" style="display:none" >
<select name="lm2" style="width:120px; display:none" ID="lm2" >
<option value="0" selected="true">——请选择——</option>
<option value="1" >1</option>
<option value="2">2</option>
<option value="3">3</option>
<option value="4">4</option>
<option value="5">5</option>
<option value="6">6</option>
<option value="7">7</option>
<option value="8">8</option>