i want that when i select value from 1st drop down box according to selected value values of 2nd drop down box changes and on selecting value from 2nd drop down values of 3rd drop down changed according to 2nd drop down selected value how can i achive this i know some javascript and jquery needed but i m new in javascript and jquery please some body help me out thanx in advanc

Put your second and subsequent selects into their own "parent elements" like a div or a span. Then "create" the entire new select inside the relevant parent element - innerHTML - using the onClick or onChange event.

Something like -

<select onChange(nextParentElement.innerHTML=nextSelect(SelectedOption))>