i want to call a jquery function on load of the page

I want to call a jquery function on load of the page. There is also another Javascript getting called onload of the body tag.

You can do it like this:

$(function() {
  //do something
});

Or if you already have the function, like this:

function myFunction() {
  //do something
}

You can call it like this:

$(myFunction);

Both of the above are equivalent to $(document).ready(function);, they're just shortcuts.

No problem - they won't conflict with each other:

$(window).load(function() {...});

or...

$(document).ready(function() {...});

Use the second one if you don't need to wait for images and other external dependencies. It simply waits for the DOM to be "ready" (i.e., completely constructed).

There is a jQquery handler called .ready() that will do what you want. It executes with the DOM is ready. See also Use Onload or ready? for a discussion about the differences between ready and onload.