Question

javascript获取select的值怎么会是undefined,哪里出错了

<form id="form1" name="form1" method="post" action="">
<select name="select1" id="select1" onchange="chsel();">
<option value="test1">test1</option>
<option value="test2">test2</option>
</select>

</form>

<script type="text/javascript">
//<![CDATA[
function chsel(){
alert(this.value);
}

//]]></script>

Answer 1

<form id="form1" name="form1" method="post" action="">
<select name="select1" id="select1" onchange="chsel();">
<option value="test1">test1</option>
<option value="test2">test2</option>
</select>
</form>
<script type="text/javascript">
//<![CDATA[
function chsel(){
var value=document.getElementById("select1");
alert(value.value);
}
//]]>
</script>

Answer 2

onchange="chsel(this.value);"

function chsel(optionValue){
alert(optionValue);
}

Answer 3

没有传对象过去。。
function chsel(e){
alert(e.value);

onchange="chsel(this);"

这样试试看