var solutiontimer;
function startSolutionTimer() {	solutiontimer = setInterval("solutionOff()", 500); }
function resetSolutionTimer() {	clearTimeout(solutiontimer); }
function solutionOn(lyr) {
    resetSolutionTimer();
    document.getElementById("main_text").innerHTML=document.getElementById(lyr + "Solution").innerHTML;
    document.getElementById("contenthome").style.backgroundImage="url(images/"+lyr+"_box.jpg)";
}
function solutionOff() {
    try {
        document.getElementById("main_text").innerHTML=document.getElementById("defaultSolution").innerHTML;
        document.getElementById("contenthome").style.backgroundImage="url(images/home_box.jpg)";
        resetSolutionTimer();   
    } catch(e) {
        resetSolutionTimer();
    }   
}