怎么移除a 标签的onclick事件
<html><head><title>JavaScript</title></head><body><hr><a id="a1" href="#" onclick="alert('onclick未移除')">11</a><input type=button onclick="removea_click()" value="移除" /><script> function removea_click() { document.getElementById('a1').onclick = "";alert("移除成功") }</script></body></html>