Handling Keyboard Events in Javascript

Guys if u have seen the moving of pictures on pressing a key in FB , FLICKR etc. Can also be done by you all now.
The code for Handling the keyboard button press etc is shown below

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document.onkeydown = keyHit;


var thisPic = 0;


function keyHit(evt) {


var myPix = new Array("List down your images here (ex. "images/callisto.jpg",


               "images/callisto123.jpg")");

var imgCt = myPix.length-1;


var ltArrow = 37;


var rtArrow = 39;


var thisKey;


if (evt) {


thisKey = evt.which; 


}else { 


thisKey = window.event.keyCode;


}


if (thisKey == ltArrow) { 


chgSlide(-1); 


}else { 


if (thisKey == rtArrow) { 


chgSlide(1);


} 


}


return false;





function chgSlide(direction) {


thisPic = thisPic + direction;


if (thisPic > imgCt) {


thisPic = 0;


}


if (thisPic < 0) {


thisPic = imgCt;


}


document.getElementById("myPicture").src = myPix[thisPic];


}


}