<select >标签有 value 属性，存储的就是当前所选择的选项值。
可以按如下方式获取：
var select = document.getElementById('mySelect')alert( select.value )
JS 控制select选中项，代码如下：<html>
<script type="text/javascript">
var selectedValue = '<%= request.getAttribute("line")%>'
function changeSelected(){
jsSelectItemByValue(document.getElementById("mySelect"),selectedValue)
}
function jsSelectItemByValue(objSelect,objItemText) {
for(var i=0i<objSelect.options.lengthi++) {
if(objSelect.options[i].value == objItemText) {
objSelect.options[i].selected = true
break
}
}
}
</script>
<body onload="changeSelected()">
<select id="mySelect" name="mySelect">
<option value="0">0</option>
<option value="1">1</option>
<option value="2">2</option>
<option value="3">3</option>
</select>
</body>
</html>
