Can I continue with a previous prevent link?

Question

I have this link:

$('.popup-window').click(function (e) {
    e.preventDefault();

    $.ajax({
        ...
    })
});

which is a .NET LinkButton (a link that call a javascript, not a real href). I want to prevent Default if ajax return some (let say, false). Else, if true, continue with that link handler.

How can I do it?

P.S. I need that e.preventDefault(); at the beginning, else .NET handler will act immediatly.

I can return true, but inside $.ajax's success?!?! It does not make sense there... — markzzz, Sep 20 '13 at 08:53
Consider that your ajax is async..o you setup it for being sync? You can re-fire the event later, using a flag to determine if it's refired or not — Irvin Dominin, Sep 20 '13 at 08:55

Frederik.L · Answer 1 · 2013-09-20T09:59:49.427

I think I understand what you're looking for.

Here's my idea on it: use a data attribute on the DOM element to decide weither default event should be prevented or not. Initially, the event is prevented but the ajax has the power to "unlock?" it, then fire it again. It's a little bit of custom work but it may do the trick:

var $popupWindow=$('popup-window');

// initially "tell" the LinkButton to prevent default
$popupWindow.data('prevent-default', 1);

// the click event (initially prevents default)
$popupWindow.click(function(e){
    var $this=$(this);

    if ($this.data('prevent-default')==0) { // if "unlocked"

        // "lock" it again (default isn't prevented)
        $this.data('prevent-default', 1);

    } else { // if "locked"
        // default is prevented
        e.preventDefault();

        // test if it should be unlocked
        $.ajax({
            // ...
        }).done(function(data){
            if (data.length>0 && data.response==false) {
                // set the attribute so it shouldn't prevent default
                $this.data('prevent-default', 0);

                // trigger this click (should let the event fire completely)
                $this.trigger('click');
            }
        });
    }
});

UPDATE:

An alternative could be to add a Page Method.

(See: Using jQuery to directly call ASP.NET AJAX page methods)

This would reduce the mechanics to somethink like this:

$('popup-window').click(function(e){
    e.preventDefault();

    $.ajax({
        // ...
    }).done(function(data){
        if (data.length>0 && data.response==false) {
            $.ajax({
                type: "POST",
                url: "YourPage.aspx/YourMethod",
                data: "{}",
                contentType: "application/json; charset=utf-8",
                dataType: "json",
                success: function(msg) {
                    // Replace the div's content with the page method's return.
                    $("#Result").text(msg.d);
                }
            });
         }
     });
});

It doesn't work! When I `$this.trigger('click');`, next I catch the `// "lock" it again (default isn't prevented)` statement, but the .NET linkbutton it is not executed. — markzzz, Sep 20 '13 at 09:42
I guess that jquery won't do the postback after all... but you can use a Page Method and call it through ajax. Look here: http://encosia.com/using-jquery-to-directly-call-aspnet-ajax-page-methods/ — Frederik.L, Sep 20 '13 at 09:51

score 1 · Accepted Answer · edited May 23 '17 at 12:20

1

You can use the __doPostBack() js function to trigger the postback in your AJAX callback.

The only thing is that you need to pass in the id of the control causing the postback, e.g.

 __doPostBack('btnPopup', null);

you can see more on this function in this question: How to use __doPostBack()

edited May 23 '17 at 12:20

Community

1
1

answered Sep 20 '13 at 09:40

RobH

3,604
1
23
46

But it doesnt call the `onclick` method of that LinkButton :O – markzzz Sep 20 '13 at 09:49
`__doPostBack(link.attr('id'), "OnClick");` do the post back, but not call the LinButton method on the click. – markzzz Sep 20 '13 at 09:54
In page_load look in the `Request["__EVENTTARGET"]` for the id of your control and call the method. – RobH Sep 20 '13 at 10:11

score 0 · Answer 3 · answered Sep 20 '13 at 08:48

 $('.popup-window').click(function (e) {
data = '?sample=1' //serialized data here
callback    = function(json){
    if(json.returnVar!=true){ //check if returnVar is not true
        e.preventDefault();   //prevent redirect if not true
    }
};

$.ajax({
      type: 'POST',
      url: "../ajaxcall.php", //the url to call for ajax here
      data: data,
      success: callback,
      dataType: 'json'
    });
});

Try this, let me know if you can't understand the code

No. I need to put the prevent default at the start of the code, otherwise .NET framework acts immediatly. — markzzz, Sep 20 '13 at 08:49

Can I continue with a previous prevent link?

3 Answers3