How to know if there is any Ajax Request and ajax Success

问题

I wonder how can I code this

//if there is any ajax request
   $("#loader").css("display","block");
//on success:
    $("#loader").css("display","none");

Note : i am not going to code it again and again in my each ajax request function. i want it Genric. so that my script knows if there is any ajax request do $("#loader").css("display","block"); and if there is any ajax success do $("#loader").css("display","none");

回答1:

The magical thing you are looking for is jQuery.ajaxStart() and jQuery.ajaxStop(). You might also find jQuery.ajaxComplete() useful.

Example:

$("#loader").ajaxStart(function() {
   $(this).show();
}).ajaxStop(function() {
   $(this).hide();
});

You should use the hide() and show() methods instead of changing the display CSS attribute.

回答2:

Take a look at $.ajaxStart and $.ajaxEnd when you wire up your app in $.document(ready):

$.ajaxStart(function(){
  $("#loader").css("display", "block");
})
.ajaxStop(function(){
  $("#loader").css("display", "none");
});

UPDATE forgot about ajaxStop...@Cory's answer reminded me. Updated my answer.

回答3:

These other solutions are great but I am not sure they address your concern of calling your $("#loader") CSS changes on start and success.

May be something like this:

$(document).ajaxStart(function() {

  // do something on start
  $("#loader").css("display","block");

}).ajaxError(function(e, xhr, settings) {
  // do something on error
  $("#loader").css("display","none");

}).ajaxSuccess(function() {

  // do something on success
  $("#loader").css("display","block");

});

Check out this properly working example: http://jsbin.com/ocovoq/3/edit#preview

回答4:

If you fire off two or three ajax calls, ajaxStop will only fire when the last one is done.

var isMakingAjaxCall;

$(document).ready(function () {

    // Loading Screen for Ajax Calls
    $("#loader").hide();
    $("#loader").ajaxStart(function () {
        isMakingAjaxCall = true;
        RepositionLoading();
        $("#loader").fadeIn();
    });
    $("#loader").ajaxStop(function () {
        $("#loader").fadeOut();
        isMakingAjaxCall = false;
    });
});

function RepositionLoading() {
    $("#loader").css('left', "20px");
    $("#loader").css('top', "20px");
};

来源：https://stackoverflow.com/questions/9740939/how-to-know-if-there-is-any-ajax-request-and-ajax-success

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javascript

jquery

javascript-events