<html>
<head>
<script type="text/javascript">
function displaymessage()
{
var aaa=document.getElementById("select")[3].options[window.document.getElementById("select").selectedIndex].text
alert(aaa)
}
</script>
</head><body>
<form>
<table>
<tr>
<select name="select" id="select">
<option value="lack_no"></option>
<option value="lack_in">1111</option>
<option value="lack_out" selected ="selected">1112</option>
</tr><tr>
<select name="select" id="select">
<option value="lack_no"></option>
<option value="lack_in">2222</option>
<option value="lack_out" selected ="selected">22221</option>
</tr><tr>
<select name="select" id="select">
<option value="lack_no"></option>
<option value="lack_in">3333</option>
<option value="lack_out" selected ="selected">33331</option>
</tr>
</table>
<input type="button" value="Click me!" onclick="displaymessage()" >
</form>
</body>
</html>
代码如上,注意nanme和id都是一样。我想button按下后,提示第三个下拉框选中的值。以上的JS代码有误,但是不知道如何写,请大神看看。
<html>
<head>
<script type="text/javascript">
function displaymessage()
{
var aaa=document.getElementsByName("select")[2].value;
alert(aaa)
}
</script>
</head><body>
<form>
<table>
<tr>
<select name="select" id="select">
<option value="lack_no"></option>
<option value="lack_in">1111</option>
<option value="lack_out" selected ="selected">1112</option>
</tr><tr>
<select name="select" id="select">
<option value="lack_no"></option>
<option value="lack_in">2222</option>
<option value="lack_out" selected ="selected">22221</option>
</tr><tr>
<select name="select" id="select">
<option value="lack_no"></option>
<option value="lack_in">3333</option>
<option value="lack_out" selected ="selected">33331</option>
</tr>
</table>
<input type="button" value="Click me!" onclick="displaymessage()" >
</form>
</body>
</html>
<html>
<head>
<script type="text/javascript">
function displaymessage()
{
var aaa=document.getElementsByName("select")[2].options[document.getElementsByName("select")[2].selectedIndex].innerHTML;
alert(aaa)
}
</script>
</head><body>
<form>
<table>
<tr>
<select name="select" id="select">
<option value="lack_no"></option>
<option value="lack_in">1111</option>
<option value="lack_out" selected ="selected">1112</option>
</tr><tr>
<select name="select" id="select">
<option value="lack_no"></option>
<option value="lack_in">2222</option>
<option value="lack_out" selected ="selected">22221</option>
</tr><tr>
<select name="select" id="select">
<option value="lack_no"></option>
<option value="lack_in">3333</option>
<option value="lack_out" selected ="selected">33331</option>
</tr>
</table>
<input type="button" value="Click me!" onclick="displaymessage()" >
</form>
</body>
</html>
可以用
var obj=document.getElementsByTagName("select")[2];
alert(obj.options[obj.selectedIndex].text);