Mazes - The Essential Guide to HTML5 - page 251

Code Explanation

}

function getkeyAndMove(event) {

var keyCode;

if(event == null)

{

keyCode = window.event.keyCode;

window.event.preventDefault();

}

else

{

keyCode = event.keyCode;

event.preventDefault();

}

switch(keyCode)

{

case 37: //left arrow

mypent.moveit(-unit,0);

break;

case 38: //up arrow

mypent.moveit(0,-unit);

break;