全局变量未在JavaScript中更新

Question

I've seen several posts on here about how to update a Javascript global variable. I'm trying to use it as a toggle, so that when the function runs again it does the opposite of what it just did (or, that is, whatever I've set it to do. )

It's not working, and I'm frusturated because I'm getting no errors from the developer console, either.

var display_menu_toggle = false;
function display_menu() {
        if (display_menu_toggle == true) {
        document.getElementById('barometer').style.display = "none";
        document.getElementById('finance').style.display = "none";
        return false;
    }
    document.getElementById('barometer').style.display = "block";
    document.getElementById('finance').style.display = "block";
    display_menu_toggle = true;
    return true;
}

Answer 1

As others have said, you aren't changing the value of display_menu_toggle for both conditions. Consider:

var display_menu_toggle = false;

function display_menu() {
    document.getElementById('barometer').style.display = display_menu_toggle? "none" : '';
    document.getElementById('finance').style.display = display_menu_toggle? "none" : '';
    display_menu_toggle = !display_menu_toggle;
}

It's usually best to toggle style.display between none and '' (empty string) so that when not hidden, the element returns to its default or inherited style, whatever that might be.