var txt = ''; var xmlhttp = new XMLHttpRequest(); xmlhttp.onreadystatechange = function(){ if(xmlhttp.status == 200 && xmlhttp.readyState == 4){ txt = xmlhttp.responseText; } }; xmlhttp.open("GET","./content/test.json",false); xmlhttp.send(); console.log(txt) var json = JSON.parse(txt); alert(json.src); if (json.type == "img") { var contenttype = "img" } else { var contenttype = "iframe" } var options = ' src = "'; var options = options.concat(json.src); var options = options.concat('"'); var content = document.createElement(contenttype,[options]); document.body.appendChild(content)