window.onload=function (){
    var oBtn = document.getElementsByTagName('input');
    var oDiv = document.getElementById('div2');
    var oAtt = ["width","height","background-color","display","display"];
    var oVal =["500px","400px","red","none","block"];
    
    for (var i=0; i < oAtt.length; i++) { 
        oBtn[i].index=i; 
        oBtn[i].onclick=function(){                   
            
            oDiv.style.cssText=''; 
            changeStyle(oDiv,oAtt[this.index],oVal[this.index]); } 
    } 
} 

function changeStyle (obj,att,val)
{ 
    obj.style[att]=val;
}