iframe style="display: none; height: 0; width: 0;" id="link-preview-iframe" src="" name="link-preview-iframe"></iframe> 
        <script>
        <![CDATA[

        var opacityTimeout;
        var contentTimeout;
        var transitionDurationMs = 100;

        var iframe = document.getElementById('link-preview-iframe')
        var tooltipWrapper = document.getElementById('tooltip-wrapper')
        var tooltipContent = document.getElementById('tooltip-content')

        var linkHistories = {};

        func