I'd spent a lot of time layout the timesheet page, designing the form, and help text etc. I didn't really want to destroy the visuals if a record was locked, I wanted it just the same, but 'non-active'.
This is where JQuery is simply awesome. Understanding 'selectors' and the power they can give you, with only very simple construction is key.
In this example imagine a page that has a div within it, the div has a id of 'divLabel'. Within that div there is a form. The code below will disable all the input elements within that div. Every single one of them. In one line of code. How cool is that.
$('#divLabel :input').attr('disabled', true);
What its actually doing is adding the disabled attribute to each input, then setting the value to 'true'.
Get familiar with how JQuery selectors work, the docs are here: http://api.jquery.com/category/selectors/