Using tuanvt's idea in the accepted answer, I wrote a jQuery plugin that does the job.
I track when the user presses the up, down, page-up and page-down keys to tell when they're in the autocomplete box. All other keys imply they've left it.
I ensure that we only apply these rules to textboxes: all other input elements behave normally.
Opera already does a pretty good job of what I was trying to achieve, so I don't enforce my rules in that browser - otherwise the user would have to press enter twice.
Tested in IE6, IE7, IE8, Firefox 3.5.5, Google Chrome 3.0, Safari 4.0.4, Opera 10.00.
It's available on jquery.com as the SafeEnter plugin. For your convenience, the code for release 1.0 is as follows:
// jQuery plugin: SafeEnter 1.0
// http://plugins.jquery.com/project/SafeEnter
// by teedyay
//
// Fires an event when the user presses Enter, but not whilst they're in the browser's autocomplete suggestions
//codesnippet:2e23681e-c3a9-46ce-be93-48cc3aba2c73
(function($)
{
$.fn.listenForEnter = function()
{
return this.each(function()
{
$(this).focus(function()
{
$(this).data('safeEnter_InAutocomplete', false);
});
$(this).keypress(function(e)
{
var key = (e.keyCode ? e.keyCode : e.which);
switch (key)
{
case 13:
// Fire the event if:
// - we're not currently in the browser's Autocomplete, or
// - this isn't a textbox, or
// - this is Opera (which provides its own protection)
if (!$(this).data('safeEnter_InAutocomplete') || !$(this).is('input[type=text]') || $.browser.opera)
{
$(this).trigger('pressedEnter', e);
}
$(this).data('safeEnter_InAutocomplete', false);
break;
case 40:
case 38:
case 34:
case 33:
// down=40,up=38,pgdn=34,pgup=33
$(this).data('safeEnter_InAutocomplete', true);
break;
default:
$(this).data('safeEnter_InAutocomplete', false);
break;
}
});
});
};
$.fn.clickOnEnter = function(target)
{
return this.each(function()
{
$(this)
.listenForEnter()
.bind('pressedEnter', function()
{
$(target).click();
});
});
};
})(jQuery);