jsfddle page

I am currently using bootstrap modal , which is a jquery plugin to create a popup box, here is its documentation, only few lines, so it takes a minute to read only

I encountered problem in 3 aspect :

How can i define the size of the modal(pop up box)? I tried:

<div class="modal" id="myModal" style="width:800px;height:900px;">

but it does not display correctly.

And how can i hide the modal by default, it currently display when i enter the page

I tried the method in doucment

    $(document).ready(function() {
$('#myModal').modal("hide");
} );

but not working as well.

Thank you