I hope someone could explain to me how to script a button element on my web page. 

I am new to javascript and html. So I hope what I'm asking makes sense.

The idea is that the contents of an element changes to content obtained from a php file on the server.

I am using php to serve html5. I have tried the following:

```
<a onclick="document.getElementByID("myID").innerHTML(src="_document_with_new_content.php")") class="myClass"></a>.

```

my results are that the styles on my elements are lost and the desired elements do not load into the container element.

I also get no success from the ajax:

```
<a onclick="document.getElementByID("myID").load(src="_document_with_new_content.php")></a>

```

I am obviously doing it wrong, but can anyone help with this?