preloaded = false;
function PreloadImages() {
	if(document.images) {
		img_button_1 = new Image(); img_button_1.src = 'images/button_1.jpg';
		img_button_1_o = new Image(); img_button_1_o.src = 'images/button_1_o.jpg';

		img_button_2 = new Image(); img_button_2.src = 'images/button_2.jpg';
		img_button_2_o = new Image(); img_button_2_o.src = 'images/button_2_o.jpg';

		img_button_3 = new Image(); img_button_3.src = 'images/button_3.jpg';
		img_button_3_o = new Image(); img_button_3_o.src = 'images/button_3_o.jpg';

		img_button_4 = new Image(); img_button_4.src = 'images/button_4.jpg';
		img_button_4_o = new Image(); img_button_4_o.src = 'images/button_4_o.jpg';

		img_button_5 = new Image(); img_button_5.src = 'images/button_5.jpg';
		img_button_5_o = new Image(); img_button_5_o.src = 'images/button_5_o.jpg';

		preloaded = true;
	}
}
function ImgOn(imgName){
	if(preloaded) document[imgName].src = eval('img_' + imgName + '_o.src');
}
function ImgOff(imgName){
	if(preloaded) document[imgName].src = eval('img_' + imgName + '.src');
}