Driver code
let x1 = 0 , y1 = 4 , x2 = 0 , y2 = - 9 ; let x3 = 2 , y3 = 0 , x4 = - 1 , y4 = 0 ; if ( checkOrtho ( x1 , y1 , x2 , y2 , x3 , y3 , x4 , y4 ) == true ) document . write ( " " ) ; else document . write ( " " ) ;