<script language="javascript">
function i(vl){
if(vl==6){
document.getElementById("div1").innerHTML="<input type='text' value='' name='t1' id='t1'>";
}else{
document.getElementById("div1").innerHTML="";
}
}
</script>
<form>
<select onchange="i(this.value)">
<option value=1>1</option>
<option value=2>2</option>
<option value=3>3</option>
<option value=4>4</option>
<option value=5>5</option>
<option value=6>其他</option>
</select>
<div id="div1"></div>
</form>