string_len
This function returns the length of the string.
double string_len(string the_string)
Parameters:
the_string
The string that will be evaluated.
Return value:
A double with the length of the string.
Remarks:
If an empty string is passed, the function will return 0.
An alternative method to string_len is to call the length method on the string variable in question, remembering that a string is an array of characters. This function has been implemented for convenience and completeness.
Example:

    void main()
    {
    alert("string_len test", string_len("Hello, I am a string!")); //output should be 21
    }