onChange problem

[wxdqz]

i have a php site

then i have:

param1<input type=text name="params[]">
param2<input type=text name="params[]">
param3<input type=text name="params[]">
param4<input type=text name="params[]">
total<input type=text name="total">

then i added onChange events in each input but couldnt work it out
i want to change the value of total each time any input box is changed