jQuery Masonry and Ajax Append Items?

var mediaItemContainer = $( '#container' );
mediaItemContainer.masonry( {
    columnWidth:  '210px',
    itemSelector: '.item'
} );
$( mediaItemContainer ).prepend( '<div class="item">foo</div>' );
$( mediaItemContainer ).masonry( 'reloadItems' );
$( mediaItemContainer ).masonry( 'layout' );

Solution

It appears that the masonry function expects a jQuery object as its second parameter and not a raw HTML string. You should be able to fix this by wrapping the success callback parameter like so:

jQuery.ajax({
    type: "POST",
    url: ajax_url,
    data: ajax_data,
    cache: false,
    success: function (html) {
        if (html.length > 0) {
            var el = jQuery(html);
            jQuery("#content").append(el).masonry( 'appended', el, true );
        }
    });
});

Had a similar problem and instead used the following line (converted for your code). Sorry, I don't recall where I found it.

In your code replace this:

jQuery("#content").append(el).masonry( 'appended', el, true );

With this:

jQuery("#content").append(el).masonry( 'reload' );

http://masonry.desandro.com/methods.html