i have two two field 1)select type options 2) input type text..in first page...

first page:-

Voucher Type:<SELECT name="voucher_type"><option value="" selected></option><option VALUE="BP">BP</option><option VALUE="BR">BR</option><option VALUE="JV">JV</option></select>
Voucher No.:<input type="text" name="voucherno" size="4" >
in second page, i want that it display Voucher Type+Voucher No..

for example when i enter values in Voucher Type is BP and Voucher No. is 1...it should be display as BP0001...

if i enter Voucher No. is 2.. then it displays BP0002.....vice versa..

Note that: if i enter 1 then it would be 0001
if 10 then it would display 0010,
if 100 then 0100,
if 1000 then same 1000

Note that it wuld join the Voucher Type and Voucher No...

for ex--BP0001, BP0010, BP0120, BP1500

help me...