Is using javascript eval() safe for simple calculations in inputs?

Question

I would like to allow user to perform simple calculations in the text inputs, so that typing 2*5 will result in 10. I\'m replacing everything but digits with an empty string

Answer 1

That is safe, not because you are sanitizing it, but because it's all entered by the user and run in their own browser. If they really wanted to enter malicious code, they could do it anyway by using firebug or web inspector, or even using a bookmarklet. Thankfully, there isn't much you can do maliciously with javascript except lock up your own browser :)