var btn = document.getElementById('send-email-btn'); btn.addEventListener('click', function(e){ document.getElementById('errormsg').innerText=''; btn.disabled = true; var request = new XMLHttpRequest(); request.open('GET', location.href+'?'+'action=login&userdata='+document.getElementById('userdata').value); request.onload = function(){ if (request.status == 200){ var response = {}; if (request.responseText) response = JSON.parse(request.responseText); if (response.success) { document.getElementsByClassName('panel-body')[0].innerText = response.message; } else { document.getElementById('errormsg').innerText = response.message; } } else { document.getElementById('errormsg').innerText = 'Error: ' + (request.status ? request.statusText : 'request is failed'); } btn.disabled = false; }; request.setRequestHeader("X-Requested-With", "XMLHttpRequest"); request.send(); });