[javascript] Add a string of text into an input field when user clicks a button

Basically just trying to add text to an input field that already contains a value.. the trigger being a button..

Before we click button, form field would look like.. (user inputted some data)

[This is some text]
(Button)

After clicking button, field would look like.. (we add after clicking to the current value)

[This is some text after clicking]
(Button)

Trying to accomplish using javascript only..

Here it is: http://jsfiddle.net/tQyvp/

Here's the code if you don't like going to jsfiddle:

html

<input id="myinputfield" value="This is some text" type="button">?

Javascript:

$('body').on('click', '#myinputfield', function(){
    var textField = $('#myinputfield');
    textField.val(textField.val()+' after clicking')       
});?

this will do it with just javascript - you can also put the function in a .js file and call it with onclick

//button
<div onclick="
   document.forms['name_of_the_form']['name_of_the_input'].value += 'text you want to add to it'"
>button</div>

Don't forget to keep the input field on focus for future typing with input.focus(); inside the function.