function switchTab(tab)
{
    switch(tab)
    {
        case 'description':
            document.getElementById("descriptionTab").style.display = "block";
            document.getElementById("shippingTab").style.display = "none";
            document.getElementById("specificationsTab").style.display = "none";
            document.getElementById("tabs").className = null;
            document.getElementById("descriptionBtn").className = "active";
            document.getElementById("shipBtn").className = "";
            document.getElementById("specsBtn").className = "";
            break;

        case 'shipping':
            document.getElementById("descriptionTab").style.display = "none";
            document.getElementById("shippingTab").style.display = "block";
            document.getElementById("specificationsTab").style.display = "none";    
            document.getElementById("tabs").className = "secondTab";
            document.getElementById("shipBtn").className = "active";
            document.getElementById("descriptionBtn").className = "";
            document.getElementById("specsBtn").className = "";
            break;

         case 'specs':
            document.getElementById("descriptionTab").style.display = "none";
            document.getElementById("shippingTab").style.display = "none";
            document.getElementById("specificationsTab").style.display = "block";
            document.getElementById("tabs").className = "thirdTab";
            document.getElementById("shipBtn").className = "";
            document.getElementById("descriptionBtn").className = "";
            document.getElementById("specsBtn").className = "active";
            break;
     }
}