Game Not Detecting Collision Between Character and border

All my collision is working accept when the character collides with the border. I want the character to re-spawn so when the character collides with the border I would use his code:

 left = 10;
 var reLeft = {'left':left + "px"};
 $('#char').css(reLeft);
 top = 10;
 var reTop = {'top':top + "px"};
 $('#char').css(reTop);

But it does not do anything when the character collides with it.