How to detect an empty value when user presses ok on prompt (and previously empties the prompt field)? I need to overwrite the old value with the new (empty) value. I'm doing this:
var oldVal = 'something';
var newVal = prompt("Enter new value:", oldVal);
Currently it returns null if user empties value and clicks ok.
But at the same time I need to check for null value because if user clicks 'cancel', it will return null, which I don't want as new value.
I have see other comment that seem like solved your problem, but I think it might can no t be the best answer or solution here is your code
if (newVal == "") {
//action
}
it might seem work, but it might probably cause a problem or a little bug, is that the user can just type two blank or white-space to bypass your code, here is my solution
If (newVal.trim() == "") {
//action
}
When user hits OK without entering any value, it returns NaN and you can check it by isNaN() function.