function Button1_onclick()
{
var divone=document.getElementById("ModifyDiv");
if(!divone)
{
divone=document.createElement("Div");
divone.id="ModifyDiv";
divone.style.width="200px";
divone.style.height="180px";
divone.innerHTML="aaaaa";
document.getElementById("aa").appendChild(divone);
}
}
function Button2_onclick()
{
var divone=document.getElementById("ModifyDiv");
if(divone){
divone.parentNode.removeChild(divone);
}
}
function Button3_onclick(){
alert(document.getElementById("ModifyDiv").innerHTML);
}