function imgInit()
{
		// preloading images
		if ( document.images )
		{
			btn0_over = new Image(); btn0_over.src="graphics/btn_0_0on.png";
			btn0_out = new Image(); btn0_out.src  ="graphics/btn_0_0.png";
			btn1_over = new Image(); btn1_over.src="graphics/btn_0_1on.png";
			btn1_out = new Image(); btn1_out.src  ="graphics/btn_0_1.png";
			btn2_over = new Image(); btn2_over.src="graphics/btn_0_2on.png";
			btn2_out = new Image(); btn2_out.src  ="graphics/btn_0_2.png";
			btn3_over = new Image(); btn3_over.src="graphics/btn_0_3on.png";
			btn3_out = new Image(); btn3_out.src  ="graphics/btn_0_3.png";
			btn4_over = new Image(); btn4_over.src="graphics/btn_0_4on.png";
			btn4_out = new Image(); btn4_out.src  ="graphics/btn_0_4.png";
			btn5_over = new Image(); btn5_over.src="graphics/btn_0_5on.png";
			btn5_out = new Image(); btn5_out.src  ="graphics/btn_0_5.png";
			btn6_over = new Image(); btn6_over.src="graphics/btn_0_6on.png";
			btn6_out = new Image(); btn6_out.src  ="graphics/btn_0_6.png";
		}
}

// event handlers
function overBtn( btnName )
{
		if ( document.images )
			eval('document.getElementById("'+btnName+'").src='+btnName+'_over.src');
}

function outBtn( btnName )
{
		if ( document.images )
			eval('document.getElementById("'+btnName+'").src='+btnName+'_out.src');
}

function imgLoad()
{
	outBtn('btn0');
	outBtn('btn1');
	outBtn('btn2');
	outBtn('btn3');
	outBtn('btn4');
	outBtn('btn5');
	outBtn('btn6');
}