How to submit an HTML form on loading the page?

You don't need Jquery here! The simplest solution here is (based on the answer from charles):

<html>
<body onload="document.frm1.submit()">
   <form action="http://www.google.com" name="frm1">
      <input type="hidden" name="q" value="Hello world" />
   </form>
</body>
</html>

You can try also using below script

<html>
<head>
<script>
function load()
{
document.frm1.submit()
}
</script>
</head>

<body onload="load()">
<form action="http://www.google.com" id="frm1" name="frm1">
<input type="text" value="" />
</form>
</body>
</html> 

Do this :

$(document).ready(function(){
     $("#frm1").submit();
});