Javascript – Document.Ready() is not working after PostBack

asp.netcjavascriptjqueryuser-controls

I have a page that contains a user control within an update panel. $(document).ready(function() ) { is called and executes the code correctly when the page firsts loads but if the user clicks a button (within the user control), the document.ready() doesn't get called (document.load, onload also don't work)

I have researched this on the net and found similar problems but nothing that can explain why this isn't working. What other causes can there be for document.ready not working?

Best Answer

This will be a problem with partial postback. The DOM isn't reloaded and so the document ready function won't be hit again. You need to assign a partial postback handler in JavaScript like so...

function doSomething() {
   //whatever you want to do on partial postback
}

Sys.WebForms.PageRequestManager.getInstance().add_endRequest(doSomething);

The above call to add_endRequest should be placed in the JavaScript which is executed when the page first loads.

Related Solutions

Javascript – How to manage a redirect request after a jQuery Ajax call

I read this question and implemented the approach that has been stated regarding setting the response HTTP status code to 278 in order to avoid the browser transparently handling the redirects. Even though this worked, I was a little dissatisfied as it is a bit of a hack.

After more digging around, I ditched this approach and used JSON. In this case, all responses to AJAX requests have the status code 200 and the body of the response contains a JSON object that is constructed on the server. The JavaScript on the client can then use the JSON object to decide what it needs to do.

I had a similar problem to yours. I perform an AJAX request that has 2 possible responses: one that redirects the browser to a new page and one that replaces an existing HTML form on the current page with a new one. The jQuery code to do this looks something like:

$.ajax({
    type: "POST",
    url: reqUrl,
    data: reqBody,
    dataType: "json",
    success: function(data, textStatus) {
        if (data.redirect) {
            // data.redirect contains the string URL to redirect to
            window.location.href = data.redirect;
        } else {
            // data.form contains the HTML for the replacement form
            $("#myform").replaceWith(data.form);
        }
    }
});

The JSON object "data" is constructed on the server to have 2 members: data.redirect and data.form. I found this approach to be much better.

Javascript – How to check if element is visible after scrolling

This should do the trick:

function isScrolledIntoView(elem)
{
    var docViewTop = $(window).scrollTop();
    var docViewBottom = docViewTop + $(window).height();

    var elemTop = $(elem).offset().top;
    var elemBottom = elemTop + $(elem).height();

    return ((elemBottom <= docViewBottom) && (elemTop >= docViewTop));
}

Simple Utility Function This will allow you to call a utility function that accepts the element you're looking for and if you want the element to be fully in view or partially.

function Utils() {

}

Utils.prototype = {
    constructor: Utils,
    isElementInView: function (element, fullyInView) {
        var pageTop = $(window).scrollTop();
        var pageBottom = pageTop + $(window).height();
        var elementTop = $(element).offset().top;
        var elementBottom = elementTop + $(element).height();

        if (fullyInView === true) {
            return ((pageTop < elementTop) && (pageBottom > elementBottom));
        } else {
            return ((elementTop <= pageBottom) && (elementBottom >= pageTop));
        }
    }
};

var Utils = new Utils();

Usage

var isElementInView = Utils.isElementInView($('#flyout-left-container'), false);

if (isElementInView) {
    console.log('in view');
} else {
    console.log('out of view');
}

Best Answer

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Javascript – How to check if element is visible after scrolling

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