Question

How can I restrict any special characters entered in the textbox?
I have a textbox where the user can enter in the textbox to validate if the url exists in the db. Before I hit the db I want to make sure there is no special characters entered in the textbox

for an example if some user try to enter something like:
)(*&<>&*^&*^&*$%#!@#$http://www.cnn.com!@#$%^&*()

Before they paste or type the url with special characters how can I not allowed in the textbox?

The only expection to this is: & (ampersand) is allowed if it is in between the url something like this:

http://cnn.com/news/latest.html&id=1

Answer 1

The simplest answer is to just make a method to strip characters on the client side.

$('#myTextBox').keyup(function()
{
     var santizedValue = '';
     for(var j = 0; j < this.value.length; j++)
        if(this.value[j].toLower() == 'a' || this.value[j].toLower() == 'b' ... )
           sanitizedValue += this.value[j];

        //Alternatively; convert the character to integer and check the ASCII range for a-z + &

     this.value = sanitizedValue;
});

You make a similar method on your server (just in case the client doesnt have javascript or defeats the script).