[javascript] How to link external javascript file onclick of button

It is totally possible, i did something similar based on the example of Mike Sav. That's the html page and ther shoul be an external test.js file in the same folder

example.html:

<html>
<button type="button" value="Submit" onclick="myclick()" >
Click here~!
<div id='mylink'></div>
</button>
<script type="text/javascript">
function myclick(){
    var myLink = document.getElementById('mylink');
    myLink.onclick = function(){
            var script = document.createElement("script");
            script.type = "text/javascript";
            script.src = "./test.js"; 
            document.getElementsByTagName("head")[0].appendChild(script);
            return false;
    }
    document.getElementById('mylink').click();
}
</script>
</html>

test.js:

alert('hello world')