JQuery + Menu Onchange +mySql Help

Table 1
Itm_id | itm_name |
----------------------
1 | Transport|
2 | Food |

Table 2
Id | itm_id | list_name
-------------------------------------
1 | 2 | Pizza
2 | 2 | Burger


<form id="form1" name="form1" method="post" action="">
Select Group
<select name="select1" id="select1">
</select>
<br />
Select Item
<select name="select2" id="select2">
</select>
</form>


"Select1" should display table1.itm_name

"Select2" should display table2.list_name [sending a select query from "Select1" Onchange Event]

Plz help me to solve this problem as I'm new in JQuery world..