js怎么动态获取ID值

[YJ_Scorpion]

<a href="javascript:;" id="btnUpload1">投票</a>
<a href="javascript:;" id="btnUpload2">投票</a>
<a href="javascript:;" id="btnUpload3">投票</a>
<script type="text/javascript">
//定义获取对象的方法
function $(id) {
return document.getElementById(id);
}
var btnUpload = $(btnUpload1);

function uploadFun() {
var xhr = new XMLHttpRequest();
xhr.onreadystatechange = function(e) {
btnUpload1.innerHTML = "已投票";
}
xhr.open("POST", "votepage.php?id=&voteid="+formdata, true);
}
val.addEventListener("click", uploadFun, false);
</script>

JS里的那个btnUpload怎么动态获取上面的ID呀？btnUpload1`3不能用手写的，这里只有三个，实际上有无数个，怎么能动态获取一下。

[slwsss]

事件怎么写的？ <a href="javascript:;" id="btnUpload1" onclick="alert(this.id)">投票</a>

[天际的海浪]

function uploadFun() {
	var _this = this;
	var xhr = new XMLHttpRequest();
	xhr.onreadystatechange = function(e) {
		_this.innerHTML = "已投票";
	}
	xhr.open("POST", "votepage.php?id=&voteid="+formdata, true);
}