js\nl2br

function nl2br (str, is_xhtml) {
    // *     example 1: nl2br('Kevin\nvan\nZonneveld');
    // *     returns 1: 'Kevin<br />\nvan<br />\nZonneveld'
    // *     example 2: nl2br("\nOne\nTwo\n\nThree\n", false);
    // *     returns 2: '<br>\nOne<br>\nTwo<br>\n<br>\nThree<br>\n'
    // *     example 3: nl2br("\nOne\nTwo\n\nThree\n", true);
    // *     returns 3: '<br />\nOne<br />\nTwo<br />\n<br />\nThree<br />\n'
    
    var breakTag = (is_xhtml || typeof is_xhtml === 'undefined') ? '<br />' : '<br>';
    return (str + '').replace(/([^>\r\n]?)(\r\n|\n\r|\r|\n)/g, '$1' + breakTag + '$2');
}