如何在Ajax之后添加JQuery?

There are containers that have dropdowns, initialized using materializecss

$('.dropdown-button').dropdown({
        inDuration: 300,
        outDuration: 225,
        constrain_width: true, // Does not change width of dropdown to that of the activator
        hover: false, // Activate on click
        alignment: 'right', // Aligns dropdown to left or right edge (works with constrain_width)
        gutter: 0, // Spacing from edge
        belowOrigin: false // Displays dropdown below the button
    });

Later I add more containers to the page using ajax, but Dropdowns do not work on them anymore ...

How to fix it?