for(var i = 0; i < confs.length; i++ ) {

   var configData = conf[i].data

   var xhr = new XMLHttpRequest();
   xhr.open('GET', url, true);
   xhr.send();
   xhr.onreadystatechange = function() {
       if (this.readyState != 4) return;
       if (this.status != 200) {
           return;
       }

       myMethod(configData);
   };
}

var xhr = new XMLHttpRequest();
   xhr.open('GET', url, true);
   xhr.configData = confs[i].data;
   xhr.onreadystatechange = function() {
       if (this.readyState != 4) return;
       if (this.status != 200) {
           return;
       }
       myMethod(this.configData);
   };
   xhr.send();

let configData = confs[i].data;