Added Navigation through Left Arrow and Right Arrow

I have recently added Navigation through Left Arrow and Right Arrow of keyboard. Hope it will help. If you loved the functionality and would like to provide the feature to your blog readers then you are welcome.

Find the code here for implementing Next/Prev using Keyboard Right and Left Arrow Key:

// Simulate Left/Right for Older/Newer post
// jQuery(document).keydown(function(e) {
jQuery(document).delegate('*', 'keydown', function (e) {
    lnkPrev = '';
    lnkNext = '';
    if (jQuery('#pagenavi').length) {
        lnkPrev = jQuery('#pagenavi .newer a')[0];
        lnkNext = jQuery('#pagenavi .older a')[0];
    } else if (jQuery('#postnavi').length) {
        lnkPrev = jQuery('#postnavi .prev a')[0];
        lnkNext = jQuery('#postnavi .next a')[0];
    }
    if (lnkPrev || lnkNext) {
        switch (e.which) {
        case 39: // right arrow
            if (lnkNext !== '') lnkNext.click();
            break;
        case 37: // left arrow
            if (lnkPrev !== '') lnkPrev.click();
            break;
        default:
            return;
        }
        e.preventDefault();
    }
});
To add toolTip to your next/Prev Links:
jQuery('#pagenavi .newer a').attr('title', 'Left and Right Arrow Key Enabled');
jQuery('#pagenavi .older a').attr('title', 'Ctrl + Left and Right Arrow Key Enabled');
jQuery('#postnavi .prev a').attr('title', 'Ctrl + Left and Right Arrow Key Enabled');
jQuery('#postnavi .next a').attr('title', 'Ctrl + Left and Right Arrow Key Enabled');

Please check the class names used for links in your Theme. #pagenavi is parent DIV in my case that is holding concerned links.

Thanks.

Update (Dec, 2013):
Add another check in condition:
if (e.ctrlKey) { }

Without this, when user in any input element (Search, TextArea, etc) and pressed back/Forward button then page will get changed. So, now, with the above code, Next and Prev will work with Ctrl + Left/Right arrow.