更新UL字段的Javascript

如何让js向以下UL id自动完成插入值

我已经试过了,但是没有进展:

document.getElementById("autocomplete").value=output[6];

和

var item = document.getElementById("autocomplete").childNodes[0];
item.replaceChild(output[6], item.childNodes[0])

:

<div data-role="fieldcontain" class="containing-element-1">
    <legend class="ui-block-a padding"><b>Site:</b></legend>
    <div class="ui-block-b"><ul id="autocomplete" name="autocomplete" data-role="listview" data-inset="true" data-filter="true" data-filter-placeholder="..." data-filter-theme="f"></ul></div>
    <div class="ui-block-b" id="contractor_list_div"><select name="contractor_list" id="list_contractor" data-mini="true" class="inputreq contractor_wide"></select></div>                      
</div>