check a textbox for invalid characters using js and regular expressions

Question

I am having a hard time figuring out how RegExp work.

I need to rewrite some ASP code into html and js, and I\'ve hit an obstacle in this part:

Answer 1

[^#%&*:<>?/{|}]+ looks like a valid expression to me (although typically regular expressions are enclosed in forward-slashes). It's basically checking to see of the filename contains any of the illegal characters within the square brackets (apart from the caret ^ which indicates negation).

function regexValidator(control) {
        var val = $(control).val();
        if(val == undefined || val == '') {

            $(control).attr("class", "invalid");
        } 
        else if(val.match(/[^#%&*:<>?/{|}]+/)) {
            // Valid
        }
        else {
            // Invalid
        }
    }