Trying to make a simple online php editor

Hi codemirror(s),

I’m trying to make an online web based php editor that will run through the browser that I can install on website so I can edit the files right in the browser. I was blown away to discover the codemirror project and am excited to use this revolutionary project!

So before I get in too heavy I just want to start with a code editing window, that has html, php and javascript code completion in it. Is this kind of thing easy to set up? I was thinking about modifying a demo file and just adding in the features I want. Is this a good idea? This is what I was gonna start out with.

 <script type="text/javascript">
  window.onload = function() {
    editor = CodeMirror(document.getElementById("code"), {
      mode: "text/html",
      extraKeys: {"Ctrl-Space": "autocomplete"},
      value: document.documentElement.innerHTML

What would I add to that to get javascript and php code completion and syntax?

Thanks for any tips in the right direction!