CODEWITHSUNDEEP
javascriptjqueryalert
Uggers2k
Uggers2k

Reputation: 351

Detect if an alert or confirm is displayed on a page

Is there a way using JavaScript or jQuery to detect if a confirm or alert box is being displayed?

Upvotes: 33

Views: 51379

Answers (6)

Andrii Karaivanskyi
Andrii Karaivanskyi

Reputation: 2002

To add to @user113716's answer you can rely on time. I assume that if confirm dialog took less than 200 ms, it is blocked by browser. Below I return true if confirm dialog is blocked (by default it returns false, the code is in TypeScript).

    let oldConfirm = window.confirm;
    window.confirm = (msg) => {
        let time = new Date().getTime();
        let conf = oldConfirm(msg);

        return new Date().getTime() - time > 200 ? conf : true;
    }

Upvotes: 3

DeadlyChambers
DeadlyChambers

Reputation: 5284

If you want to detect if these are being blocked. You will have to do your own thing with the message you will be dispalying but override the native alert/confirm.

window.nativeAlert = window.alert;
window.alert = function (message) {
var timeBefore = new Date();
var confirmBool = nativeAlert(message);
var timeAfter = new Date();
if ((timeAfter - timeBefore) < 350) {
    MySpecialDialog("You have alerts turned off, turn them back on or die!!!");
  }
}

window.nativeConfirm = window.confirm;
window.confirm = function (message) {
var timeBefore = new Date();
var confirmBool = nativeConfirm(message);
var timeAfter = new Date();
if ((timeAfter - timeBefore) < 350) {
    MySpecialDialog("You have alerts turned off, turn them back on or die!!!");
}
 return confirmBool;
}

Obviously I have set the time to 3.5 milliseconds. But after some testing we were only able to click or close the dialogs in about 5 milliseconds plus

Upvotes: 3

user113716
user113716

Reputation: 322612

If you wanted to run some code when an alert() fires, you could try something like this:

I've only tested in Chrome, so I'm not sure about browser support.

Example: http://jsfiddle.net/Q785x/1/

(function() {
    var _old_alert = window.alert;
    window.alert = function() {
                     // run some code when the alert pops up
        document.body.innerHTML += "<br>alerting";
        _old_alert.apply(window,arguments);
                     // run some code after the alert
        document.body.innerHTML += "<br>done alerting<br>";
    };
})();

alert('hey');
alert('you');
alert('there');

Of course this only lets you run code before and after an alert. As @kander noted, javascript execution is halted while the alert is displayed.

Upvotes: 30

Dan Beam
Dan Beam

Reputation: 3927

You could do this if you want to...

(function () {

    // remember the normal alert
    var oldAlert = (function(){ return this.alert; }()),
        oldConfirm = (function(){ return this.confirm; }());

    // inject ourself into the window.alert and window.confirm globals
    alert = function (msg) {
        oldAlert.call(document, msg);
        document.onAlert(msg);
    };
    confirm = function (msg) {
        var result = oldConfirm.call(document, msg);
        document.onConfirm(msg, result);
        return result;
    };

    // these just chill and listen for events
    document.onAlert = function (msg) {
        window.console && console.log('someone alerted: ' + msg);
    };
    document.onConfirm = function (msg) {
        window.console && console.log('someone was asked: ' + msg);
        window.console && console.log('and they answered: ' + (msg ? 'yes' : 'no'));
    };

}());

The downside to this is that

Upvotes: 7

kander
kander

Reputation: 4306

Confirm and alert boxes are blocking events - Javascript code execution is halted while these are displayed. So no - you can not detect if one is currently being displayed, as far as I know.

Upvotes: 4

Raynos
Raynos

Reputation: 169551

No there is not. You can check that the return value of a confirm command is indeed true or false but you cant check whether there visually there.

These things are part of the browser not part of the DOM. I'm sure there's a dirty hack that works for IE because it's a bastardized child of the windows OS.

Upvotes: 9

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