<input type="text" name="aaa">和一个
<select name="bbb"><option value="1">1</option><option value="2">2</option><option value="6">6</option></select>
<button onclick="alert(check())">Check</button>
<script>
function check(){
var found = false;
for(i=0;i<document.all.bbb.options.length;i++){
if(document.all.bbb.options[i].text==document.all.aaa.value)
found = true;
}
return found;
}
</script>
<select name="bbb"><option value="1">1</option><option value="2">2</option><option value="6">6</option></select>
<button onclick="alert(check())">Check</button>
<script>
function check(){
var found = false;
for(i=0;i<document.all.bbb.options.length;i++){
if(document.all.bbb.options[i].text==document.all.aaa.value)
found = true;
}
return found;
}
</script>
<input type="text" name="aaa" onchange="chk()">
<select name="bbb"><option value="1">1</option><option value="2">2</option><option value="6">6</option></select>
</form>
<script language="JavaScript">
<!--
function chk(){
var str = "不存在该选项"
var fm1 = document.all("fm1")
for(var i=0;i<fm1.bbb.length;i++){
if(fm1.bbb[i].value==fm1.aaa.value)str="存在该选项"
}
alert (str)
}
//-->
</script>
var len =document.formName.bbb.length
for(var i=0;i<len;i++)
{
if(document.formName.aaa.value==document.formName.bbb.options[i].value)
{
alert("??")
break
}
}你的bbb是不是value和text总是相同?
<select name="b">
<option value=a>a</option>
</select>
<input type=button value=click onclick="check()">
<script>
function check(){
var norecord=true;
for(var i=0;i<b.options.length&&norecord;i++)
if(b.options[i].value==a.value)
norecord=false;
if(norecord)
alert("no");
else
alert("yes");
}
</script>
<select name="bbb"><option value="1">1</option><option value="2">2</option><option value="6">6</option></select>
<button onclick="alert(check())">Check</button>
<script>
function ifExist(key){
var Exist = false;
var menu = documnet.forms[0].bbb
for(i=0;i<menu.options.length;i++){
if(menu.options[i].value==key)
Exist = true;
}
return Exist;
}
</script>
其中key 几位你要检测的值。
<input type="text" name="aaa" onChange="textChange(this.value);">
<select name="bbb">.........</select>
<script language="javascript">
function textChange(value){
bbb.value=value;
if(bbb.selectedIndex== -1){
alert("你填入的值不存在,请重新填写."); }
}
</script>