function switch1(div) {
 var option=['one','two','three'];
 for(var i=0; i<option.length; i++) {
 if (document.getElementById(option[i])) {
 obj=document.getElementById(option[i]);
 obj.style.display=(option[i]==div)? "block" : "none";
 }
 }
 }

 window.onload=function () {switch1('one');}