Disable save-to-file button until there is some text

chrome/browser/resources/net_internals/export_view.js

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 /**
  * This view displays options for exporting the captured data.
  */
 var ExportView = (function() {
   'use strict';
 
@@ skipping 11 matching lines @@
 
     var privacyStrippingCheckbox = $(ExportView.PRIVACY_STRIPPING_CHECKBOX_ID);
     privacyStrippingCheckbox.onclick =
         this.onSetPrivacyStripping_.bind(this, privacyStrippingCheckbox);
 
     this.saveFileButton_ = $(ExportView.SAVE_FILE_BUTTON_ID);
     this.saveFileButton_.onclick = this.onSaveFile_.bind(this);
     this.saveStatusText_ = $(ExportView.SAVE_STATUS_TEXT_ID);
 
     this.userCommentsTextArea_ = $(ExportView.USER_COMMENTS_TEXT_AREA_ID);
+    this.enableSaveFileButton_(false);
+    this.userCommentsTextArea_.onkeyup = this.onUserCommentsUpdated_.bind(this);
 
     // Track blob for previous log dump so it can be revoked when a new dump is
     // saved.
     this.lastBlobURL_ = null;
 
     // Cached copy of the last loaded log dump, for use when exporting.
     this.loadedLogDump_ = null;
   }
 
   ExportView.TAB_ID = 'tab-handle-export';
@@ skipping 76 matching lines @@
       }
       this.createLogDump_(this.onLogDumpCreated_.bind(this));
     },
 
     /**
      * Creates a log dump, and either synchronously or asynchronously calls
      * |callback| if it succeeds.  Separate from onSaveFile_ for unit tests.
      */
     createLogDump_: function(callback) {
       // Get an explanation for the dump file (this is mandatory!)
-      var userComments = this.getNonEmptyUserComments_();
-      if (userComments == undefined) {
-        return;
-      }
+      var userComments = this.userCommentsTextArea_.value;
 
       this.setSaveFileStatus('Preparing data...', true);
 
       var privacyStripping = SourceTracker.getInstance().getPrivacyStripping();
 
       // If we have a cached log dump, update it synchronously.
       if (this.loadedLogDump_) {
         var dumpText = log_util.createUpdatedLogDump(userComments,
                                                      this.loadedLogDump_,
                                                      privacyStripping);
         callback(dumpText);
         return;
       }
 
       // Otherwise, poll information from the browser before creating one.
       log_util.createLogDumpAsync(userComments,
                                   callback,
                                   privacyStripping);
     },
 
     /**
      * Sets the user comments.
      */
     setUserComments_: function(userComments) {
       this.userCommentsTextArea_.value = userComments;
+      this.onUserCommentsUpdated_();
     },
 
     /**
-     * Fetches the user comments for this dump. If none were entered, warns the
-     * user and returns undefined. Otherwise returns the comments text.
+     * User comments are updated.
      */
-    getNonEmptyUserComments_: function() {
-      var value = this.userCommentsTextArea_.value;
-
-      // Reset the class name in case we had hilighted it earlier.
-      this.userCommentsTextArea_.className = '';
-
-      // We don't accept empty explanations. We don't care what is entered, as
-      // long as there is something (a single whitespace would work).
-      if (value == '') {
-        // Put a big obnoxious red border around the text area.
-        this.userCommentsTextArea_.className =
-            'export-view-explanation-warning';
-        alert('Please fill in the text field!');
-        this.userCommentsTextArea_.focus();
-        return undefined;
-      }
-
-      return value;
+    onUserCommentsUpdated_: function() {
+      this.enableSaveFileButton_(this.userCommentsTextArea_.value != '');
     },
 
     /**
      * Creates a blob url and starts downloading it.
      */
     onLogDumpCreated_: function(dumpText) {
       var textBlob = new Blob([dumpText], {type: 'octet/stream'});
       this.lastBlobURL_ = window.URL.createObjectURL(textBlob);
 
       // Update the anchor tag and simulate a click on it to start the
       // download.
       var downloadAnchor = $(ExportView.DOWNLOAD_ANCHOR_ID);
       downloadAnchor.href = this.lastBlobURL_;
       downloadAnchor.click();
 
       this.setSaveFileStatus('Dump successful', false);
     }
   };
 
   return ExportView;
 })();