function dochange(){
alert('cliced button by js function');
}
function changecolor(){
var dd1=document.getElementById("d1");
var dd2=document.getElementById("d2");
dd1.className="blueback";
dd2.className="yellowback";
}
function changetext(){
var dd1=document.getElementById("d1");
var dd2=document.getElementById("d2");
dd1.innerHTML="Bonjour";
dd2.innerHTML="Mohamed";
}