Question

I have a survey in which there are numerous text inputs taking numerical value each of which has a pair of increment/decrement buttons. I have a working function as follows:

HTML:

<div class="text-input-wrapper">
    <input type="text" />
    <div class="buttons inc-dec">
        <button class="increment">Increment</button>
        <button class="decrement">Decrement</button>
    </div>
</div>

function incDec(btnClass)   {

    var input       = $(this).closest('.text-input-wrapper').find('input');
    var inputVal    = $(this).closest('.text-input-wrapper').find('input').val();

    if ($(this).hasClass('increment')) {
        if (inputVal.length == 0) {
            ($(input).val('1'));
        }
        else {
            inputVal++;
            $(input).val(inputVal);
        }
    } // increment

    else if ($(this).hasClass('decrement')) {
        if (inputVal.length == 0) {
            ($(input).val('0'));
        }
        else {
            inputVal--;
            $(input).val(inputVal);
        }
    } // decrement

    return false;

} // function incDec

Now I need to enable incrementing and decrementing value using the UP & DOWN keys; I took a stab with the following but with no joy:

$(document).keydown( function(eventObject) {
    // UP arrow
    if(eventObject.which==38) {
        var btnClass = "increment";
    } else

    // DOWN arrow
    if(eventObject.which==40) {
        var btnClass = "decrement";
    }
    incDec(btnClass);

I’d greatly appreciate some clarification as to how to go about firing the increment/decrement using the up/down keys,

Many thanks in advance,

svs

Answer 1

Your problem is that your incDec function is not designed to take the class as an input parameter – it uses the object that calls the event (i.e. the click event on a button).

It’s a bit hacky, but how about something like below? You assign the click handler to each button then invoke the relevant button’s click-event.

$( function ( ) {
    $('button').click( incDec );

    $('input').keydown( function(eventObject) {

        // UP arrow
        if(eventObject.which==38) {
            var btnClass = "increment";
        } else

        // DOWN arrow
        if(eventObject.which==40) {
            var btnClass = "decrement";
        }

        // Invoke the click event for the inc/dec button inside the containing div.
        $('button.'+btnClass, $(this).parent( )).click( );
    });
});

Here’s a jsfiddle with two such boxes. when you use the up/down arrow keys while inside a text-box it increments/decrements correctly. http://jsfiddle.net/zJBEN/