dynatree

Use the setAttribute method: document.getElementById(‘item1’).setAttribute(‘data’, “icon: ‘base2.gif’, url: ‘output.htm’, target: ‘AccessPage’, output: ‘1’”); But you really should be using data followed with a dash and with its property, like: <li … data-icon=”base.gif” …> And to do it in JS use the dataset property: document.getElementById(‘item1’).dataset.icon = “base.gif”;