<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312" />
<title>無標題文檔</title>
</head>
城市:
<select id="name" name="name"
οnkeydοwn="clearSelect(this,event);"
οnkeypress="writeSelect(this,event);" style="width:70px;">
<option value="">廣州</option>
<option value="test1">深圳</option>
<option value="test2">北京</option>
<option value="test3">珠海</option>
</select>
<script>
function clearSelect(obj,e)
{
opt = obj.options[0];
opt.selected = "selected";
if((e.keyCode== 8) ||(e.charCode==8))//使用退格（backspace）鍵實現逐字刪除的編輯功能
{
opt.value = opt.value.substring(0, opt.value.length>0?opt.value.length-1:0);
opt.text = opt.value;
}
}
function writeSelect(obj,e)
{
opt = obj.options[0];
opt.selected = "selected";
opt.value += String.fromCharCode(e.charCode||e.keyCode);
opt.text = opt.value;
}
function forbidBackSpace()//爲了在IE中，避免backspace的返回上一頁功能，和本下拉框的編輯功能衝突，需要禁掉backspace的功能。forbidBackSpace可以寫在<body οnkeydοwn="forbidBackSpace();">中。
{
if((event.keyCode == 8) && (event.srcElement.type != "text" && event.srcElement.type != "textarea" && event.srcElement.type != "password"))
{
event.keyCode = 0;
event.returnValue = false;
}
}
</script>
<body>
</body>
</html>
