Standard error messages

[GoogleCodeExporter]

What steps will reproduce the problem?
1. Create a form, do not specify any error message value for min_length
2. Type in a value that does not meet the the min_length


What is the expected output? What do you see instead?
-I would expect a nice standard error message like "must be at least $(max)d 
characters in length"
-However, render_ajax_fields returns null as the value of the error message for 
min_length.  We certainly shouldn't have to define these messages for every 
single field for every single form.
-I've noticed the required validator does return a standard message.  
max_length does not, I assume other do not as well.
-This also causes an exception in the ValidationError object in the javascript 
since msg is null.  I think it should fall back and just say "Error"?

    for(idx in params) {
        msg = msg.replace(idx, params[idx]);
    }


What version of the product are you using? On what operating system?
0.1 - Windows 7

Original issue reported on code.google.com by owendea...@gmail.com on 28 Feb 2012 at 8:39