SO - 4594631

by qwertymk

HTML

<table id="bar">
    <tr>
        <td>hello</td>
        <td class="foo">there</td>
    <tr>
    <tr>
        <td>two</td>
    </tr>
    <tr>
        <td class="foo">three</td>
    </tr>
    <tr>
        <td>four</td>
    </tr>
</table>
        <a href="#" onclick="run();">run</a>

JavaScript

run = function(){
    td = document.getElementsByTagName('td');
    for (var  i = 0; i < td.length; i++) {
        if (td[i].className === 'foo')
            if (!td[i].style.display)
                td[i].style.display = 'none';
            else    
                td[i].style.display = '';
    }
}