jumpyfield

/*
JUMPYFIELD is a simple little thing that makes the focus jump between fields when they reach maxlength.
Usage:

$(".myInputFields").jumpy();

jumpy also accepts an optional array of default values that count the fields as "empty". Example:

$(".myInputFields").jumpy(["YY","MM","DD"]);

*/

jQuery.fn.jumpy = function(defaultValues) {

	// Save the context in the element so that we know which fields to jump between.
	this.data("_jumpySelector", this.selector);
	
	this.keyup(function(event) {

		var tabKeyCode = 9;
		if (event.keyCode == tabKeyCode) {
			// Ignore accidental tabbing as a result of the user not knowing about the
			// jumpy fields, and trying to tab after filling out a field.
			var previousJumpy = jQuery(this)._getPreviousJumpyField();		
	
			var isEmpty = jQuery(previousJumpy).val().length == 0;
			var hasDefaultValue = jQuery(previousJumpy).data("_defaultValue") == jQuery(previousJumpy).val();
			if ( isEmpty || hasDefaultValue )
				previousJumpy.focus();
			return false;
		}
		if (jQuery(this).val().length >= parseInt(jQuery(this).attr("maxlength"))) {
			var nextjf = jQuery(this)._getSubsequentJumpyField();
			jQuery(nextjf).focus();
		}
	});
};

jQuery.fn._getSubsequentJumpyField = function() {
    var lastIterated = null;
    var subsequent = null;
	var originator = this[0];

	
    jQuery(this.data("_jumpySelector")).each(function(index, iterated) {
		if (subsequent == null) {
            if (lastIterated == originator) {
                subsequent = this;
            }
            lastIterated = this;
        }
    });
    return subsequent;
}

jQuery.fn._getPreviousJumpyField = function () {
    var lastIterated = null;
    var previous = null;
	var originator = this[0];
	console.log("getting prev field for " + this.data("_jumpySelector"));
	
    jQuery(this.data("_jumpySelector")).each(function(index, iterated) {
        if (previous == null) {
            if (this == originator) {
                previous = lastIterated;
            }
            lastIterated = this;
        }
    });
	console.log("found" + previous);
    return previous;
}