Add minimal http client

app/js/http.js

@@ -0,0 +1,37 @@
+function getXHR(){
+    var xhr;
+    try {
+        xhr = new ActiveXObject("Msxml2.XMLHTTP");
+    } catch (e) {
+        try {
+            xhr = new ActiveXObject("Microsoft.XMLHTTP");
+        } catch (e) {
+            xhr = false;
+        }
+    }
+    if (!xhr && typeof XMLHttpRequest !== 'undefined') {
+        xhr = new XMLHttpRequest();
+    }
+    return xhr;
+}
+
+function getURL(url, params, callback) {
+    if (Object.keys(params).length > 0) {
+        var pairs = [];
+        for (key in params) {
+            pairs.push(key +'='+ encodeURIComponent(params[key]))
+        }
+        url += '?'+ pairs.join('&');
+    }
+
+    var xhr = getXHR();
+    xhr.open('GET', url, true);
+    xhr.onreadystatechange = function() {
+        if (xhr.readyState === 4) {
+            if(xhr.status === 200) {
+                callback(JSON.parse(xhr.responseText));
+            }
+        }
+    };
+    xhr.send(null);
+}