javascript regular expression to not match a word

if (!s.match(/abc|def/g)) {
    alert("match");
}
else {
    alert("no match");
}

This is what you are looking for:

^((?!(abc|def)).)*$

The ?! part is called a negative lookahead assertion. It means "not followed by".

The explanation is here: Regular expression to match a line that doesn't contain a word