Is it ok to do this:
var myString=\"Hello!\";
alert(myString[0]); // shows \"H\" in an alert window
Or should it be done with either charAt
Accessing characters as numeric properties of a string is non-standard prior to ECMAScript 5 and doesn't work in all browsers (for example, it doesn't work in IE 6 or 7). You should use myString.charAt(0) instead when your code has to work in non-ECMAScript 5 environments. Alternatively, if you're going to be accessing a lot of characters in the string then you can turn a string into an array of characters using its split() method:
var myString = "Hello!";
var strChars = myString.split("");
alert(strChars[0]);