populate form based on multiple select elements - php

Question

I want a form to have multiple drop down selects that change based on the previous selection. This is how I want it to work.
<select id="format">
<option selected="selected" value="NULL">-- Select a product Format --</option>
<option value="PS3">PS3</option>
<option value="Xbox 360">Xbox 360</option>
<option value="Wii U">Wii U</option>
</select>
So if you select PS3 you are then faced with more options for PS3 product type
<select id="ps3-product-type">
<option selected="selected" value="NULL">-- Select a product PS3 product type --</option>
<option value="chargers">chargers</option>
<option value="controllers">controllers</option>
<option value="headsets">headsets</option>
</select>
So then you select headsets for example and you get another set of final options of products
<select id="ps3-headsets">
<option selected="selected" value="NULL">-- Select a PS3 headset --</option>
<option value="product-1">product 1</option>
<option value="product 2">product 2</option>
<option value="product 3">product 3</option>
</select>
How can I do this with jquery or PHP? Please bare in mind that I will also have selects for Xbox 360 and Wii U too.
UPDATE PROGRESS:
http://jsfiddle.net/maximus83/r7MN9/639/
Here is my HTML, I have got the first set of arrays working for selecting product type, But I cant get the 3rd box working, I need 3rd box to say the product, where do I go from here.
<select id="cat">
<option val="PS3">PS3</option>
<option val="Xbox360">Xbox360</option>
<option val="WiiU">WiiU</option>
<option val="Multiformat">Multiformat</option>
</select>
<select id="item">
</select>
<select id="product">
</select>
Here is my script
PS3=new Array('Headsets(PS3)','Controllers(PS3)','Chargers(PS3)','Cables(PS3)');
Xbox360=new Array('Headsets(360)','Chargers(360)');
WiiU=new Array('Controllers(WiiU)','Headsets(WiiU)');
Multiformat=new Array('Headsets(Multi)','Chairs(Multi)','Cables(Multi)');
populateSelect();
$(function() {
$('#cat').change(function(){
populateSelect();
});
});
function populateSelect(){
cat=$('#cat').val();
$('#item').html('');
eval(cat).forEach(function(t) {
$('#item').append('<option val="#item">'+t+'</option>');
});
}

Answer 1

This should do the trick for you. It's a previously answered thread on the exact same topic - how to populate a drop down based on the value in another. It takes advantage jQuery (And I've used it before myself as reference).