function swaptabs(el,sitecolour,tabcolour,selectedtabcolour,offcolour){
        var selectedtab = document.getElementById('tab' + el);
        for (z=1;z<=6;z++)
        {
	
            //hide all image and data divs
            document.getElementById('tabimage' + z).style.display = "none";
            document.getElementById('tabdata' + z).style.display = "none";
            document.getElementById('tab' + z).style.backgroundColor = tabcolour;
            document.getElementById('readmore' + z).style.display = "none";
	    document.getElementById('a' + z).style.color = offcolour;
        } 
        document.getElementById('tabimage' + el).style.display = "block";
        document.getElementById('tabdata' + el).style.display = "block";
        document.getElementById('tab' + el).style.backgroundColor = sitecolour;
	selectedtab.getElementsByTagName('a')[0].style.color = selectedtabcolour;
        document.getElementById('tab' + el).style.color = '#fff';
        document.getElementById('readmore' + el).style.display = "block";
    }