Find an element and you can use '.text()' or '.html()' to update its value. Here is an example shows how to do this.
<div id="foo" class="easyui-tabs" style="width:600px;height:300px">
    <div title="Tab1">
        <p><label id="l-A"></label></p>
        <p><label id="l-B"></label></p>
        <p><label id="l-C"></label></p>
    </div>
</div>
<script type="text/javascript">
$(function(){
    var data = {
        A: 'Apple',
        B: 'Banana',
        C: 'Cherry'
    };
    for(var k in data){
        var v = data[k];
        $('#l-'+k).html(v);
    }
});
</script>