Displaying leading/trailing zero in text box

Hi,
i have many text boxes to input numeric values in the form. If any numeric value entered in text box it should automatically display 2 dismal zero. else if no values entered in the text box it should display 0.00 value in it .
ex : if i enter a value in the text box : 25  it should be 25.00
if doesn't enter any value in text box, it should be 0.00

...