Question

În php I would use this to see if a variable is set and then use that value, otherwise make it a zero:

    $pic_action = isset($_POST['pic_action']) ? $_POST['pic_action'] : 0;

But what is the equivalent in javascript?

I want to check if an element exists in the document, and then if it does, add it to the variable, otherwise add some other value to it, here is what I have so far:

    var areaOption = document.getElementById("element");

Thanks

Answer 1

document.getElementById("element") will return null if the element doesn’t exist — and something not-null if it exists.

Which means you should be able to do something like this :

var areaOption = document.getElementById("element");
if (areaOption) {
    // element exists
} else {
    // element doesn't exist
}

(You could also compare areaOption with null, instead of just checking if it’s non-falsy)