对于<select name="Category"> <option value="">please select</option> <option value="SCANNER">SCANNER</option> <option value="SCSI CARD">SCSI CARD</option> <option value="SOFTWARE">SOFTWARE</option> </select>可以这样:var col = document.all.Category.tags("OPTION"); if (col.length ==0) alert("select is empty.");OK?
我好像搞错你的意思了,你是要判断select选中的内容是否为空对不对呀? 可以用 var empty = false; var col = document.all.tags("SELECT"); for (i=0; i<col.length; i++) if (col[i].value == "") { empty = true; break; } if (empty) alert("EMPTY!");
var urArray=new Array("aa","bb")
alert(urArray.length)
</script>
{
if(document.formname.selectname.options[i].value=="")
alert("为空")
}
一种是只有一个 <select name="Category">
<option value="">please select</option>
<option value="SCANNER">SCANNER</option>
<option value="SCSI CARD">SCSI CARD</option>
<option value="SOFTWARE">SOFTWARE</option
</select>另一中情况是两个或者多个select
<HTML>
<script>
function test(){
with (document.formname){
for(var i=0;i<document.formname.elements.length;i++){
if(document.formname.elements[i].type=="select-one"){
for(var j=0;j<document.formname.elements[i].length;j++){
if(document.formname.elements[i].options[j].value=="")
alert("选项 "+document.formname.elements[i].options[j].text+" 的 value 处为空,不信你打开源代码看看!!")
}
}
}
}
}
</script>
<form name=formname><select name="Category">
<option value="">please select</option>
<option value="SCANNER">SCANNER</option>
<option value="SCSI CARD">SCSI CARD</option>
<option value="SOFTWARE">SOFTWARE</option
</select><select name="products">
<option value="1">请选择啊</option>
<option value="SCANNER">SCANNER</option>
<option value="SCSI CARD">SCSI CARD</option>
<option value="SOFTWARE">SOFTWARE</option
</select><select name="sum">
<option value="">请选择</option>
<option value="SCANNER">SCANNER</option>
<option value="">测试</option>
<option value="SOFTWARE">SOFTWARE</option
</select>
<br>
<input type=button onclick=test() value=test>
</form>
</HTML>
<select name="Category">
<option value="">please select</option>
<option value="SCANNER">SCANNER</option>
<option value="SCSI CARD">SCSI CARD</option>
<option value="SOFTWARE">SOFTWARE</option>
</select><select name="Category">
<option value="">请选择啊</option>
<option value="SCANNER">SCANNER</option>
<option value="SCSI CARD">SCSI CARD</option>
<option value="SOFTWARE">SOFTWARE</option>
</select>还有可能之后一个select有怎么判断?
需要同时在一个地方判断不是分开!!!
<option value="">please select</option>
<option value="">请选择啊</option>
有两处 value=空的啊
<option value="">please select</option>
<option value="SCANNER">SCANNER</option>
<option value="SCSI CARD">SCSI CARD</option>
<option value="SOFTWARE">SOFTWARE</option>
</select>可以这样:var col = document.all.Category.tags("OPTION");
if (col.length ==0) alert("select is empty.");OK?
可以用
var empty = false;
var col = document.all.tags("SELECT");
for (i=0; i<col.length; i++)
if (col[i].value == "") {
empty = true;
break;
}
if (empty) alert("EMPTY!");