javascript - Addition turns into concatenation

Question

var Height=  (rowData.length * 30) + PPPP.top + 10 ;

When i print this i get 9013510... instead of 90 +135+10 = 235. Why does mine turns into concatentaion instead of Addition.

Answer 1

You probably need to convert PPPP.top to a number, eg.

var Height = (rowData.length * 30) + parseFloat(PPPP.top) + 10;