StringExtensionsSubstringJS Method

Implements the javascript string.substring() function which differs from the C# string.Substring() method in that the 2nd argument is the index of the first character to exclude vs. the character count. The rules for handling the two indices are as described in https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/substring.

public static string SubstringJS(
	this string s,
	int startIndex,
	int beyondEndIndex = 2147483647
)

<ExtensionAttribute>
Public Shared Function SubstringJS ( 
	s As String,
	startIndex As Integer,
	Optional beyondEndIndex As Integer = 2147483647
) As String