This version sandboxes el inside an iframe to avoid weird Android Browser quirks. Requires jQuery.

has3d.js

function has3d(){
	var el = $('<p>')[0], $iframe = $('<iframe>'), has3d, t,
		transforms = {
			'webkitTransform': '-webkit-transform',
			'OTransform': '-o-transform',
			'msTransform': '-ms-transform',
			'transform': 'transform'
		};

	// Add it to the body to get the computed style
	// Sandbox it inside an iframe to avoid Android Browser quirks
	$iframe.appendTo('body').contents().find('body').append( el );

	for (t in transforms) {
		if (el.style[t] !== undefined) {
			el.style[t] = 'translate3d(1px,1px,1px)';
			has3d = window.getComputedStyle(el).getPropertyValue(transforms[t]);
		}
	}

	$iframe.remove();

	return has3d !== undefined && has3d.length > 0 && has3d !== "none";
}

Screw jQ....

function has3d(){
    var el = document.createElement("P"), iframe = document.createElement("IFRAME"), has3d, t,
        transforms = {
            'webkitTransform': '-webkit-transform',
            'OTransform': '-o-transform',
            'msTransform': '-ms-transform',
            'transform': 'transform'
        };

    // Add it to the body to get the computed style
    // Sandbox it inside an iframe to avoid Android Browser quirks+
    document.body.appendChild(iframe);
    iframe.contentDocument.body.appendChild(el);

    for (t in transforms) {
        if (el.style[t] !== undefined) {
            el.style[t] = 'translate3d(1px,1px,1px)';
            has3d = window.getComputedStyle(el).getPropertyValue(transforms[t]);
        }
    }

    document.body.removeChild(iframe);

    return has3d !== undefined && has3d.length > 0 && has3d !== "none";
}


has3d();