I am new to JavaScript, so pardon my lack of knowledge.

I am trying to code a contact form and want to get the value entered in a particular input text field as soon as a value entered by the visitor using AJAX and pass it to a PHP string so that I can show relevant information based on the value entered before hitting the submit button.

How Can I do that using jQuery?

Here are the codes I am using for the form:

<form method=post action=>

<input type=text id=name name=name />

<input type=text id=email name=email />

<input type=text id=subject name=subject />

<input type=text id=url name=url />

<input type=checkbox id=showdetails name=showdetails /> Show URL Details

<input type=submit value=Submit />

</form>`

I need the value of the URL input field to pass to a php string (as soon as the user checks the showdetails checkbok) so that I can process it in background to show information based on the url.