Заменить:
var url_pattern = /(\()((?:ht|f)tps?:\/\/[a-z0-9\-._~!$&'()*+,;=:\/?#[\]@%]+)(\))|(\[)((?:ht|f)tps?:\/\/[a-z0-9\-._~!$&'()*+,;=:\/?#[\]@%]+)(\])|(\{)((?:ht|f)tps?:\/\/[a-z0-9\-._~!$&'()*+,;=:\/?#[\]@%]+)(\})|(<|&(?:lt|#60|#x3c);)((?:ht|f)tps?:\/\/[a-z0-9\-._~!$&'()*+,;=:\/?#[\]@%]+)(>|&(?:gt|#62|#x3e);)|((?:^|[^=\s'"\]])\s*['"]?|[^=\s]\s+)(\b(?:ht|f)tps?:\/\/[a-z0-9\-._~!$'()*+,;=:\/?#[\]@%]+(?:(?!&(?:gt|#0*62|#x0*3e);|&(?:amp|apos|quot|#0*3[49]|#x0*2[27]);[.!&',:?;]?(?:[^a-z0-9\-._~!$&'()*+,;=:\/?#[\]@%]|$))&[a-z0-9\-._~!$'()*+,;=:\/?#[\]@%]*)*[a-z0-9\-_~$()*+=\/#[\]@%])/img;
с
var url_pattern = new RegExp("([\\.+])", "img"); // simplified for my sanity
При правильном экранировании строки \
до \\
<Ч />
EDIT:
var a = new RegExp("(\\()((?:ht|f)tps?:\\/\\/[a-z0-9\\-._~!$&'()*+,;=:\\/?#[\\]@%]+)(\\))|(\\[)((?:ht|f)tps?:\\/\\/[a-z0-9\\-._~!$&'()*+,;=:\\/?#[\\]@%]+)(\\])|(\\{)((?:ht|f)tps?:\\/\\/[a-z0-9\\-._~!$&'()*+,;=:\\/?#[\\]@%]+)(\\})|(<|&(?:lt|#60|#x3c);)((?:ht|f)tps?:\\/\\/[a-z0-9\\-._~!$&'()*+,;=:\\/?#[\\]@%]+)(>|&(?:gt|#62|#x3e);)|((?:^|[^=\\s'\"\\]])\\s*['\"]?|[^=\\s]\\s+)(\\b(?:ht|f)tps?:\\/\\/[a-z0-9\\-._~!$'()*+,;=:\\/?#[\\]@%]+(?:(?!&(?:gt|#0*62|#x0*3e);|&(?:amp|apos|quot|#0*3[49]|#x0*2[27]);[.!&',:?;]?(?:[^a-z0-9\\-._~!$&'()*+,;=:\\/?#[\\]@%]|$))&[a-z0-9\\-._~!$'()*+,;=:\\/?#[\\]@%]*)*[a-z0-9\\-_~$()*+=\\/#[\\]@%])", "gim");
Вышеуказанный пропуск jslint