Check if elem contains within array

fn.inArray.js

/**
 * Check if elem contains within array
 *
 * @param array
 * @param elem checking value
 * @returns {int}
 */
inArray: function(array, elem) {
    var indexOf = [].indexOf;
    if (indexOf) {
        return indexOf.call(array, elem);
    }
    for ( var i = 0, length = array.length; i < length; i++ ) {
        if ( elem === array[ i ] ) {
            return i;
        }
    }
    return -1;
}