HTML textarea prevent some text from being deleted

Question

I am making a terminal window in HTML/JavaScript and am using a textarea for input. I would like to prevent sections of the text in the textarea from being deleted. For example, if I had the text in the textarea "C:\>Random Code" I would like to prevent the user deleting the "C:\>" text. Is this possible using javascript?

Answer 1

Assuming jQuery, this script will listen for keystrokes, and if any of the required text can't be found (ie: user tries to delete it) it will add itself right back in there:

var requiredText = 'C:>';
$('textarea').on('input',function() {
    if (String($(this).val()).indexOf(requiredText) == -1) {
        $(this).val(requiredText);
    }
}