grails: grailsui : cannot access dataTable outside <gui> tag

I tried to access Datatable outside gui tag, but failed. Could some tell me why?

thanks.

the code like this:

<gui:dataT开发者_JAVA百科able id="myDataTable" .../>
<script>
    var data = GRAILSUI.myDataTable;
    alert("hi, " + data);

</script>

it ends with "hi, undefined"

Did you import the resources correctly ?

in the header ?