Capitalize first character of user input in real time with JQuery

Try this:

$(document).ready(function() {
    $('input').on('keydown', function(e) {
        if (this.value == '') {
        var char = String.fromCharCode(e.which);
            if (char.match(/^\w$/)) {
                // If is empty and we pressed a printable key...
                this.value = char.toUpperCase();
                return false;
            }
        }
    });
});

See in use here.

This works for me.

$('input').keyup(function() {
  $(this).val($(this).val().substr(0, 1).toUpperCase() + $(this).val().substr(1).toLowerCase());
});

It would be much easier to use CSS in this case:

input{
    text-transform: capitalize;
}

Update: this works when you don't want to capitalize the first letter of every word, but only the first letter of the first word:

input::first-letter{
    text-transform: uppercase;
}

Here is a fiddle I made that does what you want in Chrome. I'm not sure if it will work in other browsers.

Code:

$(document).ready(function() {
    $('input').on('keydown', function(event) {
        if (this.selectionStart == 0 && event.keyCode >= 65 && event.keyCode <= 90 && !(event.shiftKey) && !(event.ctrlKey) && !(event.metaKey) && !(event.altKey)) {
           var $t = $(this);
           event.preventDefault();
           var char = String.fromCharCode(event.keyCode);
           $t.val(char + $t.val().slice(this.selectionEnd));
           this.setSelectionRange(1,1);
        }
    });
});