var rootpath = 'http://www.veldhoenverhuizingen.nl/';

    function ChangeButton(status,title){
        if(status == 'on'){
            document.getElementById(title).src = rootpath + 'gfx/' + title + '_on.png';
        }
        if(status == 'off'){
            document.getElementById(title).src = rootpath + 'gfx/' + title + '_off.png';
        }
    }

    function BelmijScreen(){
        window.open(rootpath + 'pages/zakelijk/belmij.asp','newWin','width=350,height=350,top=60,left=60');
    }