регулярные-выражения – JavaScript: Finding the number of occurrences of characters in a string

Question:

Is there a way to count the number of certain characters in a string?

For example : how many occurrences of characters 'a', '?', '<' in the string "Hello, are you here??".

So far, doper only with regular expressions, it works, (correct? or is there another way?):

var my_text = document.getElementById('myTextArea');
var result = my_text.value.match(/[a\?\<]/g).length;

Everything is processed by onkeyup when typing, any comments will be welcome.

Answer:

("Hello, are you here??".split("a").length - 1);