function nav(idd) {
            if (idd == 1) {
                document.getElementById('one').className = '';
                document.getElementById('two').className = 'liHidden'
                document.getElementById('three').className = 'liHidden';
                document.getElementById('four').className = 'liHidden';
            }
            else if (idd == 2) {
                document.getElementById('one').className = 'liHidden';
                document.getElementById('two').className = '';
                document.getElementById('three').className = 'liHidden';
                document.getElementById('four').className = 'liHidden';
            }
            else if (idd == 3) {
                document.getElementById('one').className = 'liHidden';
                document.getElementById('two').className = 'liHidden';
                document.getElementById('three').className = '';
                document.getElementById('four').className = 'liHidden';
            }
            else if (idd == 4) {
                document.getElementById('one').className = 'liHidden';
                document.getElementById('two').className = 'liHidden';
                document.getElementById('three').className = 'liHidden';
                document.getElementById('four').className = '';
            } /* If Condition Ends here */
        }