Ajax Control Tookit is one of an important library in .NET world. It handles a lot of dynamic JavaScript things you do not want to do alone.

They have a component called MaskedEdit to handle a input formatted text like __/__/__. Take a look at the MaskedEdit example. Oh, if you use Chrome or Safari, it does not work like you expect with delete, backspace and other "special" keys. Cool, han?

This bug is from 2008, documented in issue 26978, issue 17166 and chromium issue 3341 too. These links have easy solutions: just take the code, change a couple of lines and recompile everything, but it was never merged or released.

I do not want to fork the code to change two lines, but I can just hack around JavaScript and we are fine. If you opened the MaskedEdit example in Chrome, run the code below in JavaScript console and try again. I took some pieces of code around the internet and wrote my own to work with normal and minified versions of current version of the lib.

(function() {
  if (Sys.Browser.agent == Sys.Browser.Safari) { // don't worry, to this lib Chrome is Safari
    function funcbody(f) {
      var s = f.toString();
      return s.substring(s.indexOf('{'));
    }
    try { p = Sys.Extended.UI.MaskedEditBehavior.prototype; } catch (e) { p = null; }
    if (p != null) {
      p._ExecuteNav = new Function("g", "h",
        'var c=-1,e=" ",a="",b=false,d=true,p="keypress",s="keydown",evt=g,scanCode=h;' +
        funcbody(p._ExecuteNav)
          .replace(/(g\.type==p\)if\(h==8\))/, "g.type==s||$1")
          .replace(/(== Sys\.Browser\.InternetExplorer \|\| evt\.type == \"keypress\")/,
                   "$1 || evt.type == \"keydown\""));
      }
    }
})();

The problem happens because the MaskedEditBehavior handles only keypress event (or bypass IE browsers). My hack just changes it to handle keydown too, because W3C says "dispatch this event when a key is pressed down, if and only if that key normally produces a character value".

This hack solved the issue to me and is running in production now, but it is a big reason to avoid Ajax Control Toolkit if you can. Maybe they will not support you.