// script for operating a toggle pushbutton switch
var switch_off = new Image();
switch_off.src = "gifs/red_button_up.gif";
var switch_on = new Image();
switch_on.src = "gifs/red_button_dn.gif";
var a_state = 0;
var b_state = 0;

//input A set
function a_toggle(){
//
if (a_state == 0 )
{
a_state=1;
document.images.btn_a.src = switch_on.src;
}
else
{
a_state=0;
document.images.btn_a.src = switch_off.src;
}
exor_logic();
//end
}

//input B set
function b_toggle(){
//
if (b_state == 0 )
{
b_state=1;
document.images.btn_b.src = switch_on.src;
}
else
{
b_state=0;
document.images.btn_b.src = switch_off.src;
}
exor_logic();
//end
}



//script for logic and to drive LEDs
var gled_off = new Image();
gled_off.src = "gifs/green_off.gif";
var gled_on = new Image();
gled_on.src = "gifs/green_on.gif";
var rled_off = new Image();
rled_off.src = "gifs/red_off.gif";
var rled_on = new Image();
rled_on.src = "gifs/red_on.gif";


function exor_logic() {
// the ex OR gate action is below
//light input LED A
if (a_state == 0 )
{
document.images.a_led.src = gled_off.src;
}
else
{
document.images.a_led.src = gled_on.src;
}
//light input LED B
if (b_state == 0 )
{
document.images.b_led.src = gled_off.src;
}
else
{
document.images.b_led.src = gled_on.src;
}
//light output LED which is equal to A AND B Logic
if (a_state ^ b_state)
{
document.images.q_led.src = rled_on.src;
}
else
{
document.images.q_led.src = rled_off.src;
}
//end
}