String - JavaScriptStringEncode

A value that indicates whether double quotation marks will be included around the encoded string.

Try it

public static void Main()
{	
    string input = "Hello World!";
	
	//C# Extension Method: String - JavaScriptStringEncode
	var output = input.JavaScriptStringEncode();

	Console.WriteLine("<script type=\"text/javascript\"> var msg = {0}; alert(msg); </script>", output);
	
	//C# Extension Method: String - HtmlDecode
	output = input.JavaScriptStringEncode(true);
	
	Console.WriteLine("<script type=\"text/javascript\"> var msg = {0}; alert(msg); </script>", output);
}

View Source
using System;
using System.Web;

public static partial class Extensions
{
    /// <summary>
    ///     Encodes a string.
    /// </summary>
    /// <param name="value">A string to encode.</param>
    /// <returns>An encoded string.</returns>
    public static String JavaScriptStringEncode(this String value)
    {
        return HttpUtility.JavaScriptStringEncode(value);
    }

    /// <summary>
    ///     Encodes a string.
    /// </summary>
    /// <param name="value">A string to encode.</param>
    /// <param name="addDoubleQuotes">
    ///     A value that indicates whether double quotation marks will be included around the
    ///     encoded string.
    /// </param>
    /// <returns>An encoded string.</returns>
    public static String JavaScriptStringEncode(this String value, Boolean addDoubleQuotes)
    {
        return HttpUtility.JavaScriptStringEncode(value, addDoubleQuotes);
    }
}