//preload images
 

nav_portfolio_on = new Image();
nav_portfolio_on.src = 'images/nav_portfolio_on.jpg';

nav_music_on = new Image();
nav_music_on.src = 'images/nav_music_on.jpg';

nav_details_on = new Image();
nav_details_on.src = 'images/nav_details_on.jpg';



//stop preloading images

function navOn(imName) {


		if (document.images) { 
		
		
		document.images[imName].src = "images/" + imName + "_on.jpg"
			 };

}

function navOff(imName) {

		if (document.images) { document.images[imName].src = 'images/' + imName + '_off.jpg' };

}