Drop down disabled

Question

Hello all,
here i have two dropdowns. dropdown1 and  dropdown2 
In drop down1  Have three items like item1, item2, item3
if i select item3 in dropdown1.  drop down2 will disabled. if i select item1 or item2 drop down 2 will enable....
Need code  in Jquery 
Please help me... 
Thanks in Advance.......