Capitalize the last letter in a string (with letters and numbers) using jQuery

Question

I'm using the following jQuery to capitalize the 1st letter of an input script.

$('li.capitalize input').keyup(function(event) {
    var textBox = event.target;
    var start = textBox.selectionStart;
    var end = textBox.selectionEnd;
    textBox.value = textBox.value.charAt(0).toUpperCase() + textBox.value.slice(1);
    textBox.setSelectionRange(start, end);
});

In addition, I now need to capitalize a letter at a specific position (not the first letter) in a string comprising letters and numbers.

For example: Da1234Z I need to capitalize both D and Z.

How can I do this?

Maybe i'm paranoid but this sounds a lot like a homework question. — MageeWorld, Oct 04 '16 at 16:32
So, what if the string is "23fz980q7"? Are you wanting to capitalize the F and the Q? — Jonathan M, Oct 04 '16 at 16:33

score 2 · Answer 1 · answered Oct 04 '16 at 16:44

You can use this function to capitalize the n-th character of a string:

function capitalizeNth(text, n) {
    return (n > 0 ? text.slice(0, n) : '') + text.charAt(n).toUpperCase() + (n < text.length - 1 ? text.slice(n+1) : '')
}

If you know that n can't be negative you can even shorten it to:

function capitalizeNth(text, n) {
    return text.slice(0,n) + text.charAt(n).toUpperCase() + text.slice(n+1)
}

score 0 · Accepted Answer · answered Oct 07 '16 at 16:20

Thank you all. I got to capitalize the 7th letter like this:

<script>
jQuery.noConflict();
jQuery(document).ready(function($) {
$('li.capitalize input').keyup(function(event) {
var textBox = event.target;
var start = textBox.selectionStart;
var end = textBox.selectionEnd;
textBox.value = textBox.value.slice(0,7) + textBox.value.charAt(7).toUpperCase() + textBox.value.slice(8);
textBox.setSelectionRange(start, end);
});
});
</script>

Capitalize the last letter in a string (with letters and numbers) using jQuery

2 Answers2