我有这个javaScript,以查看是否选择了下拉词。如果没有显示错误消息。问题是该代码在> IE9 和 8 中起作用,但在 Chrome 。
简单的解决方案是将" 必需"属性添加到标签中,但我想知道代码不起作用的原因。
<form name="form1" action="insert.php" method="post" onsubmit="return validateForm()">
<table name="table1">
<tr>
<td>
<select name="fruits">
<option selected disabled>Please Select</option>
<option value="banana>banana</option>
<option value="apple>apple</option>
</select>
</td>
</tr>
</table>
<input type="submit" value="Submit"/>
</form>
<script type="text/javascript">
function validateForm()
{
var x=document.forms["form1"]["fruits"].value;
if (x==null || x=="")
{
alert("Please Select Fruit");
return false;
}
}
</script>
请查看此代码,required
是HTML5属性,默认情况下检查empty
值
<form name="form1" action="insert.php" method="post" onSubmit="return validateForm()">
<table name="table1">
<tr>
<td>
<select name="fruits">
<option value=" " disabled>Please Select</option>
<option value="banana">banana</option>
<option value="apple">apple</option>
</select>
</td>
</tr>
</table>
<input type="submit" value="Submit" />
</form>
<script>
function validateForm() {
var x = document.forms["form1"]["fruits"].value;
if (x == null || x == " ") {
alert("Please Select Fruit");
return false;
}
}
</script>
演示:http://jsfiddle.net/2zggm/