Remove all characters except alphanumeric and spaces with javascript

input.replace(/[^\w\s]/gi, '')

Shamelessly stolen from the other answer. ^ in the character class means "not." So this is "not" \w (equivalent to \W) and not \s, which is space characters (spaces, tabs, etc.) You can just use the literal if you need.

I know this is an old thread, but so popular that appears at the top of a Google search. So, as an alternative, the accepted answer and comment from 3limin4t0r inspired me to:

.replace(/\W+/g, " ")

IMHO

const input = document.querySelector("input");
const button = document.querySelector("button");
const output = document.querySelector("output");

button.addEventListener("click", () => {
    output.textContent = input.value.replace(/\W+/g, " ");
})

<input>
<button>Replace</button>
<p>
  <output></output>
</p>