<!DOCTYPE>
<html>
<head></head>
<body>
<div id="foo">
<a name="warns" href="">This is a sample warning</a>
<a id="3err" href="">This is a sample error</a>
</div>
<div id="bar">
<a name="warns" href="">This is another sample warning</a>
<a name="1err" href="">This is another sample error</a>
</div>
<script>
var a = document.querySelectorAll("[name=warns]")
alert(a.length)//輸出：2
var b = document.querySelector("[id=3err]")
alert(b.tagName)//報錯
var c = document.querySelectorAll("[name=1err]")
alert(c.length)//報錯
</script>
</body>
</html>
