added leading computation using the browser
added leading computation using the browser

kevinb7/processing-js,jeresig/processing-js,kevinb7/processing-js,guazipi/processing-js,baiyanghese/processing-js,guazipi/processing-js,jaredly/processing-js,jeresig/processing-js,baiyanghese/processing-js,jaredly/processing-js