Simple feature detection

feature-detection.js

/**
 * Tests if a property has a vendor prefix and returns the properly
 * property.
 *
 * @param {string} prop - Property to test
 * @param {string} propGroup - Group where the test property is located
 * @returns {*} If the property was found, it will be returned. Otherwise false
 * @private
 */
var _getVendorPrefix = function(prop, propGroup) {
    var testEl = document.createElement('fakeElement'),
        prefixes = ['', 'webkit', 'moz', 'ms', 'o'],
        i, prefix, testProp;

    // Modify the testEl
    propGroup = propGroup || '';
    if(propGroup.length) {
        testEl = testEl[propGroup];
    }

    // Loop through the vendor prefixes
    for(i in prefixes) {
        prefix = prefixes[i];

        // Vendor prefix property
        if(prefix.length) {
            prop = prop.charAt(0).toUpperCase() + prop.slice(1);
        }
        testProp = prefix + prop;

        if(testEl[testProp] !== undefined) {
            return testProp;
        }
    }
    return false;
};