// 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 switch_state = 0;


function not_toggle(){
//
if (switch_state == 0 )
{
switch_state=1;
document.images.red_btn.src = switch_on.src;
}
else
{
switch_state=0;
document.images.red_btn.src = switch_off.src;
}
not_logic();
//end
}

//script for NOT 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";

var input_a = 0;
var output_b = 0;


function not_logic() {
// the NOT gate action is below
input_a = switch_state;
output_b = !switch_state;
//light input LED
if (input_a == 0 )
{
document.images.a_led.src = gled_off.src;
}
else
{
document.images.a_led.src = gled_on.src;
}
//light output LED
if (output_b == 0 )
{
document.images.q_led.src = rled_off.src;
}
else
{
document.images.q_led.src = rled_on.src;
}
//end
}