ajax indicator before complete loading

How can I display an ajax in开发者_如何学Godicator before all the images within a website layout were loaded?

Thanks in advance.

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Use JQuery. Please.

    $("#loading").ajaxStart(function() {
        $(this).show();
    });
    $("#loading").ajaxStop(function() {
        $(this).addClass('ohmy').hide('slow');
    });