document.querySelectorAll("table tr:nth-child(2) td").forEach(function(node){
node.ondblclick=function(){
var val=this.innerHTML;
var input=document.createElement("input");
input.value=val;
input.onblur=function(){
var val=this.value;
this.parentNode.innerHTML=val;
}
this.innerHTML="";
this.appendChild(input);
input.focus();
}
});