Failed to use command "getElementAttribute" in webDrvier.

Question

Hi Microsoft guys,
I have written a practice to learn IEDC webDriver (based on the webdriver C# demo)
Everything worked ok but failed during using 'getElementAttribute'
WorkFlow:
1. open "http://www.bing.com" - passed
2. find element for "input[name='go']" - passed.
3. find element attribute "class" for #2 element by using "getElementAttribute" command
always response will be like
Response received: {"response":{"sessionId":null,"status":"unknown error","value":"Parsing error"}}
Q:
As it is a parsing error, i doubt i write the wrong joson for getElementAttribute
But i checked the msdn, i don't know where i was wrong.
Could your guys help to have a check on my code ?
http://msdn.microsoft.com/en-us/library/ie/dn768404%28v=vs.85%29.aspx
Source code
           //Execute a "get" command - Navigate to http://bing.com
            const string getCommand = @"
                ""command"": {
                    ""name"": ""get"",
                    ""parameters"": {
                        ""url"": ""http://www.bing.com""
                    ""sessionId"": ""{sessionId}""
            response = ExecuteCommand(getCommand, strSessionId);
            //"Page Loading Strategies" are not currently supported
            //"get" commands will return immediately and not wait for the page to load
            //The 20-second polling is added to wait for the page to load
            //This issue will be addressed and fixed in the next IEWebDriver release.
            WaitForPageToLoad(20, strSessionId);
            //Execute a "findElement" command - Find the Bing search field
            const string findElementCommand = @"
                ""command"": {
                    ""name"": ""findElement"",
                    ""parameters"": {
                        ""locator"": ""css selector"",
                        ""value"": ""input[name='go']""
                    ""sessionId"": ""{sessionId}""
            response = ExecuteCommand(findElementCommand, strSessionId);
            //Retrieve the ElementId from the response
            try
                strElementId = response["response"]["value"]["id"];
            catch (Exception e)
                HandleError("Exception thrown when trying to access strResponse[\"response\"][\"value\"][\"id\"] from the response.", e);
            const string getAttrCommand = @"
                ""command"": {
                    ""name"": ""getElementAttribute"",
                    ""parameters"": {
                        ""elementId"": ""{elementId}"",
                        ""name"":""title"",
                    ""sessionId"": ""{sessionId}""
            response = ExecuteCommand(getAttrCommand, strSessionId, strElementId);

Answer 1

Hi MartinLiao,
This forum is to discuss HTML, CSS and Javascript programming for IE, I think you are posting on wrong forum. I’m not familiar with WebDriver API, so what I can do is to provide code sample for WebDriver. Please refer to the following link to download it.
http://code.msdn.microsoft.com/windowsdesktop/Internet-Explorer-02ac106f.
Thank you for understanding.
Regards,
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