Question

I have a text area which gets filled in various ways including paste, keyboard input, from an autocomplete etc.

Now I want to validate this text area and if contains any combination, including multiples of some characters and if so, set it to empty.

The characters I want to filter are: tabs, new lines, spaces, carriage returns, as well as some watermark text – basically any non-meaningful character.

Note that valid text might contain special characters such as ()!#%<>,;:/||{}[] and possibly a few more.

Valid values might contain new lines, spaces etc. but will also have other valid characters (the stuff above plus 0-9, a-z, A-Z etc.)

Currently, I have the following wrapped in a jquery .change event:

<textarea cols="70" rows="3" class="cssTextarea cptEntryArea formFocus"></textarea>

$('.cptEntryArea').live('change', function(e)
{
    var myval = "";
    myval = $(this).val().trim();
    myval.replace(/\r\n|\r|\n|\u0085|\u000C|\u2028|\u2029|^\s*$|^\s+|\s+$/g, "");
    if ((myval == watermarkText) || (myval.length == 0))
    {
        $(this).val("");
        e.stopPropagation();
        return false;
    };
});

The idea is to simply blank it out if it has “non-visual” characters in it in any combination.

Any optimization or better method to get this done?

EDIT1: Looks like I can do some adjustment here as the jQuery trim is:

trim: function( text ) {
        return (text || "").replace( /^\s+|\s+$/g, "" );
    }

Answer 1

Sounds like a very strange thing to do. What is the watermarkText for? Would it not be a better idea to catch before the text is put into the textarea i.e. on keydown, return null if the ascii value < 33? Your event only fires when the item is changed/lost focus, not immediately when some text is entered.

You could try doing /mg for the regex multi-line.