Hiding / showing page parts based on form changes

Hiding / showing page parts based on form changes

I am new to jquery and am having a hard time figuring out this
problem.

I want to hide certain table rows containing form fields when a page
loads and only show them when the rel value in a select option equals
the rel value of the table row.

I'm using a non-standard attribute "rel" for this but could switch to id or class if it would be easier.

The first part is simple

$(function(){
$("tr[rel]").hide();

});

The rest I'm not sure about. I tried this:

$("select").change(function () {
$(("tr[rel]").val() == ("select").val()).("tr[rel]").show();

});

but nothing happened when the select fields were changed.

The other thing that I need to do is check the value of the select and radio
fields when the page loads and make sure that any
matching <tr> tags display.

Thanks in advance.