diff --git a/SafeExamBrowser.Browser/BrowserControl.cs b/SafeExamBrowser.Browser/BrowserControl.cs
index 54902832..3b569d43 100644
--- a/SafeExamBrowser.Browser/BrowserControl.cs
+++ b/SafeExamBrowser.Browser/BrowserControl.cs
@@ -15,6 +15,7 @@ using SafeExamBrowser.Configuration.Contracts;
 using SafeExamBrowser.Configuration.Contracts.Cryptography;
 using SafeExamBrowser.I18n.Contracts;
 using SafeExamBrowser.UserInterface.Contracts.Browser;
+using SafeExamBrowser.UserInterface.Contracts.Browser.Data;
 using SafeExamBrowser.UserInterface.Contracts.Browser.Events;
 
 namespace SafeExamBrowser.Browser
@@ -147,10 +148,15 @@ namespace SafeExamBrowser.Browser
 		/// <summary>
 		/// Executes the given Javascript code in the browser.
 		/// </summary>
-		public async void ExecuteJavascript(string javascript, System.Action<dynamic> callback)
+		public async void ExecuteJavascript(string javascript, Action<JavascriptResult> callback)
 		{
 			var result = await this.control.EvaluateScriptAsync(javascript);
-			callback(result);
+			callback(new JavascriptResult()
+			{
+				Message = result.Message,
+				Result = result.Result,
+				Success = result.Success
+			});
 		}
 	}
 }
diff --git a/SafeExamBrowser.UserInterface.Contracts/Browser/Data/JavascriptResult.cs b/SafeExamBrowser.UserInterface.Contracts/Browser/Data/JavascriptResult.cs
new file mode 100644
index 00000000..82459ff0
--- /dev/null
+++ b/SafeExamBrowser.UserInterface.Contracts/Browser/Data/JavascriptResult.cs
@@ -0,0 +1,29 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace SafeExamBrowser.UserInterface.Contracts.Browser.Data
+{
+	/// <summary>
+	/// The data resulting from a Javascript expression evaluation.
+	/// </summary>
+	public class JavascriptResult
+	{
+		/// <summary>
+		/// Indicates if the Javascript was evaluated successfully or not.
+		/// </summary>
+		public bool Success { get; set; }
+
+		/// <summary>
+		/// The error message, in case of an unsuccessful evaluation of the Javascript expression.
+		/// </summary>
+		public string Message { get; set; }
+
+		/// <summary>
+		/// The data item returned by the Javascript expression.
+		/// </summary>
+		public dynamic Result { get; set; }
+	}
+}
diff --git a/SafeExamBrowser.UserInterface.Contracts/Browser/IBrowserControl.cs b/SafeExamBrowser.UserInterface.Contracts/Browser/IBrowserControl.cs
index 7118af86..a27c5c8e 100644
--- a/SafeExamBrowser.UserInterface.Contracts/Browser/IBrowserControl.cs
+++ b/SafeExamBrowser.UserInterface.Contracts/Browser/IBrowserControl.cs
@@ -6,6 +6,7 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
  */
 
+using SafeExamBrowser.UserInterface.Contracts.Browser.Data;
 using SafeExamBrowser.UserInterface.Contracts.Browser.Events;
 
 namespace SafeExamBrowser.UserInterface.Contracts.Browser
@@ -64,7 +65,7 @@ namespace SafeExamBrowser.UserInterface.Contracts.Browser
 		/// <summary>
 		/// Executes the given Javascript code in the browser.
 		/// </summary>
-		void ExecuteJavascript(string javascript, System.Action<dynamic> callback);
+		void ExecuteJavascript(string javascript, System.Action<JavascriptResult> callback);
 
 		/// <summary>
 		/// Attempts to find the given term on the current page according to the specified parameters.
diff --git a/SafeExamBrowser.UserInterface.Contracts/SafeExamBrowser.UserInterface.Contracts.csproj b/SafeExamBrowser.UserInterface.Contracts/SafeExamBrowser.UserInterface.Contracts.csproj
index 68674df9..5eb5ab83 100644
--- a/SafeExamBrowser.UserInterface.Contracts/SafeExamBrowser.UserInterface.Contracts.csproj
+++ b/SafeExamBrowser.UserInterface.Contracts/SafeExamBrowser.UserInterface.Contracts.csproj
@@ -55,6 +55,7 @@
   </ItemGroup>
   <ItemGroup>
     <Compile Include="Browser\Data\DownloadItemState.cs" />
+    <Compile Include="Browser\Data\JavascriptResult.cs" />
     <Compile Include="Browser\Events\AddressChangedEventHandler.cs" />
     <Compile Include="Browser\Events\FindRequestedEventHandler.cs" />
     <Compile Include="Browser\Events\LoadFailedEventHandler.cs" />