test key support BEFORE creating keys

app/js/app.js

@@ -48,7 +48,8 @@
       });
     });
   }
-  testEcdsaSupport().then(function () {
+  function testKeypairSupport() {
+    return testEcdsaSupport().then(function () {
       console.info("[crypto] ECDSA is supported");
       BROWSER_SUPPORTS_ECDSA = true;
       localStorage.setItem('version', '1');
@@ -60,20 +61,24 @@
       // fix previous firefox browsers
       if (!localStorage.getItem('version')) {
         localStorage.clear();
-      localStorage.getItem('version', '1');
+        localStorage.setItem('version', '1');
       }
 
-    // DO NOT RETURN HERE
-    testRsaSupport().then(function () {
+      return false;
+    });
+  }
+  testKeypairSupport().then(function (ecdsaSupport) {
+    if (ecdsaSupport) {
+      return true;
+    }
+
+    return testRsaSupport().then(function () {
       console.info('[crypto] RSA is supported');
     }).catch(function (err) {
       console.error('[crypto] could not use either EC nor RSA.');
       console.error(err);
       window.alert("Your browser is cryptography support (neither RSA or EC is usable). Please use Chrome, Firefox, or Safari.");
     });
-
-    // RETURN HERE
-    return false;
   });
 
   var apiUrl = 'https://acme-{{env}}.api.letsencrypt.org/directory';
@@ -238,7 +243,7 @@
     if (jwk) {
       p = PromiseA.resolve(jwk);
     } else {
-      p = createKeypair();
+      p = testKeypairSupport().then(createKeypair);
     }
 
     function createAccount(jwk) {