<form name="form1">
<select name="sel" onchange="this.form.txt1.value = this.value; this.form.txt2.value = this.options[this.selectedIndex].text;">
<option value="1">a</option>
<option value="2">b</option>
<option value="3">c</option>
<option value="4">d</option>
<input type="text" name="txt1">
<input type="text" name="txt2">
</form>
<select name="sel" onchange="this.form.txt1.value = this.value; this.form.txt2.value = this.options[this.selectedIndex].text;">
<option value="1">a</option>
<option value="2">b</option>
<option value="3">c</option>
<option value="4">d</option>
<input type="text" name="txt1">
<input type="text" name="txt2">
</form>
document.AnotherForm.txt2.value = this.options[this.selectedIndex].text;
<select name="selname" onchange="ChangeSel()">
<option value="1">a</option>
<option value="2">b</option>
<option value="3">c</option>
<option value="4">d</option>
<input type="text" name="txt1">
<input type="text" name="txt2">
</form>
<script language="javascript">
function ChangeSel()
{
document.form1.txt1.value = "选择了" + document.form1.selname.value;
document.form1.txt2.value = "选择了" + document.form1.selname.options[document.form1.selname.selectedIndex].text
}
</script>