How can I implement my own document ready functionality without using jQuery

Question

I have a script that uses $(document).ready, but it doesn't use anything else from jQuery. I'd like to lighten it up by removing the jQuery dependency.

How can I implement my own $(document).ready functionality without using jQuery? I know that using window.onload will not be the same, as window.onload fires after all images, frames, etc. have been loaded.

Answer 1

Hello @kartik,

 There are three options:

1. If script is the last tag of the body, the DOM would be ready before script tag executes
2. When the DOM is ready, "readyState" will change to "complete"
3. Put everything under 'DOMContentLoaded' event listener

onreadystatechange

  document.onreadystatechange = function () {
     if (document.readyState == "complete") {
     // document is ready. Do your stuff here
   }
 }

DOMContentLoaded

document.addEventListener('DOMContentLoaded', function() {
   console.log('document is ready. I can sleep now');
});

Concerned about stone age browsers: Go to the jQuery source code and use the ready function. In that case you are not parsing+executing the whole library you're are doing only a very small part of it.

Thank You!!