JavaScript: Get URL Query Argument

Often I have the need to parse the URL query to retrieve the value of a specific named argument. There is no direct way of doing this is JavaScript, so this requires a custom function.

function findQueryArgument (strQuery, strArgumentName) {

    // Valid query?

    if (strQuery) {

        // Split the parameteres

        var arrParameters = strQuery.split("&");

        // Walk through the parameters

        for (var i = 0; i < arrParameters.length; i++) {

            // Get the key/value pair

            var arrPair = arrParameters[i].split("=");

            // Is this the event argument?

            if (arrPair[0] == strArgumentName) {

                // Has value?

                if (arrPair.length > 1) {

                    // Get the value

                    return arrPair[1];

                }

                // Not set

                break;

            }

        }

    }

    // Not found

    return '';

}

The strQuery argument is the full URL query i.e. a=val1&b=val2 etc. The full URL should not be included.
strArgumentName is the name of the argument you're looking for, i.e. a or b.

Please notice that the returned value is URL encoded. To extract the actual string value you need to use the built in JavaScript method unescape.

Here is an example:

// Query string

var strQuery = 'a=val1&b=val2';

// Get the value of the 'b' argument

var strEscaped = findQueryArgument(findQueryArgument, strQuery, 'b');

// Get the unescaped value

var strUnescaped = unescape(strEscaped);

// Display the value

alert(strUnescaped);

MS SQL: Url Encode

There is no built-in function in Microsoft SQL Server to to support URL encoding. If you want to generate URLs with arguments on the fly in stored procedures, you would have to do the URL encoding yourself. URL encoding can be implemented in several ways. Either you can create your own custom userdefined function in MS SQL or create a custom library in .NET. The library can then be called from a stored procedure.

Here I will show how you can encode your URLs using a userdefined function:

CREATE FUNCTION [dbo].[audf_Common_UrlEncode](@strUrl varchar(max))

returns varchar(max)

AS

 begin

    -- Declare variables

    declare @intCount int,

            @strChar char(1),

            @i int,

            @strUrlReturn varchar(max)

    -- Initialize variables

    set @intCount       = Len(@strUrl);

    set @i              = 1;

    set @strUrlReturn   = '';  

    -- Loop through all characters

    while (@i <= @intCount)

    begin

        -- Get the character

        set @strChar = substring(@strUrl, @i, 1)

        -- Is ASCII character?

        if @strChar LIKE '[A-Za-z0-9()''*-._! ]'

         begin

            -- Just append character

            set @strUrlReturn = @strUrlReturn + @strChar

         end

        else

         begin

            -- Encode and append character

            set @strUrlReturn =

                   @strUrlReturn +

                   '%' +

                   SUBSTRING(sys.fn_varbintohexstr(CAST(@strChar as varbinary(max))),3,2)

         end

        -- Next character

        set @i = @i +1

     end

    -- Return the encoded URL

    return @strUrlReturn

 end