Tryit Editor v2.7

Edit This Code:
<!DOCTYPE html>
<html>
<head>
<base id="myBase" href="http://www.w3schools.com/jsref/">

<script>
var _hmt = _hmt || [];
(function() {
var hm = document.createElement("script");
hm.src = "//hm.baidu.com/hm.js?73c27e26f610eb3c9f3feb0c75b03925";
var s = document.getElementsByTagName("script")[0];
s.parentNode.insertBefore(hm, s);
})();
</script>
</head>
<body>

<p>Click the button to return the value of the href attribute of the base element.</p>

<button onclick="myFunction()">Try it</button>

<p id="demo"></p>

<script>
function myFunction() {
    var x = document.getElementById("myBase").href;
    document.getElementById("demo").innerHTML = x;
}
</script>

</body>
</html>