Addition turns into concatenation

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

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

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

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

PPPP.top is probably a string. Try:

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

It's probably treating one of the values incorrectly as a string. Try using parseInt and see if that works:

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

You can use parseInt for that.

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

I have changed radix to base 10.