<head> <script type="text/javascript"> var aDivs=array('div1','div2','div3'); var lDivs=aDivs.length-1; var iDiv=0; function cycle() { iDiv++; if (iDiv > lDivs) iDiv=0; /* iDiv will contain an index into the array of div ids (aDiv) */ } </script> </head> <body> <div id="div1">Div 1</div><div id="div2">Div 2</div><div id="div3">Div 3</div><br /> <button onclick="cycle()">Cycle</button> </body>