I think I must be missing something very obvious. Using this code I want to count up and trigger a background change on a timer; however it doesn't pass the variable, each time the timer calls the function it is passing a undefined variable.

Worth noting:

• Looked at the consol - no errors


• I know Jquery would arguably be better but the site can't have jquery due to some nasty legacy issues (thats a whole other question)

The Code

<script>

/* Get the body element */

var body = document.getElementsByTagName('body')[0];

/* Call the function */

changebackground();

/* Set the starting count */

var changecount = 1;

/* Change function */

function changebackground(changecount) {

    if(changecount=1){

        body.style.backgroundImage = 'url(/templates/images/background_1.jpg)';

        changecount = 2;

    }

    else if (changecount=2) {

        body.style.backgroundImage = 'url(/templates/images/background_2.jpg)';

        changecount = 3;

    }   

    else {

        body.style.backgroundImage = 'url(/templates/images/background_3.jpg)'; 

        changecount = 1;

    }

setInterval(function(changecount){changebackground();},3000);

}

</script>