Check if first letter of word is a capital letter

Question

Is it possible in Javascript to find out if the first letter of a word is a capital letter?

Answer 1

You can do it in several ways:

var myWord = "Hello";

// with string functions
if (myWord.charAt(0) === myWord.charAt(0).toUpperCase()) { /* is upper */ }

// or for newer browsers that support array-style access to string characters
if (myWord[0] === myWord[0].toUpperCase()) { /* is upper */ }

// with regex - may not be appropriate for non-English uppercase
if (/^[A-Z]/.test(myWord) { /* is upper */ }

Note that the array-style access to characters like myWord[0] is an ECMAScript 5 feature and not supported in older browsers, so (for now) I'd probably recommend the .charAt() method.

If you need to do this test a lot you could make a little function:

function firstLetterIsUpper(str) {
   var f = str.charAt(0);   // or str[0] if not supporting older browsers
   return f.toUpperCase() === f;
}

if (firstLetterIsUpper(myWord)) { /* do something */ }