Blank fields checking

[SSG001]

i have a form on which there are 4 rows
in the one of the field user will be inputing value
and when he is entring value in the second row on blur i have put a check if he is keying the same value but it check properly when value is kept blank for both the rows fields then it doesn''t check it i tried putting trim bt still it doesnt check
how to check two blank values

[acoder]

Post your code, so we have a better idea of the problem.