Passing Value From Dropbox 2

[Steve2106]

I think that narrowing it down what I need is to get the value from the dropbox and send it to the call of the .php file.
This is the form with the dropbox which is filling with records fine.:
   <div id="dlg" class="easyui-dialog" style="width:450px;height:250px;padding:10px 20px"
        closed="true" buttons="#dlg-buttons">
       <div class="ftitle">Assign medic to practiotioner</div>
       <form id="fm" method="post" novalidate>
           <div class="fitem">
               <input class="easyui-combobox" id="dd_medicid" name="dd_medicid" style="width:350px; margin-bottom:20px" limitToList: true; data-options="
                           url:'./getmedicnames.php',
                           method:'get',
                           valueField:'medicid',
                           textField:'certname',
                      panelHeight:400,
                           label: 'Medic Name:',
                           labelPosition: 'top'
                           ">
           </div>
       </form>
   </div>
   <div id="dlg-buttons">
      <a href="javascript:void(0)" class="easyui-linkbutton c6" iconCls="icon-ok" onclick="editUser()" style="width:90px">Save</a>
      <a href="javascript:void(0)" class="easyui-linkbutton" iconCls="icon-cancel" onclick="javascript:$('#dlg').dialog('close')" style="width:90px">Cancel</a>

This is the editcode that is called.
   function editUser(){
       $('#dlg').dialog('open').dialog('setTitle','New Assignment');
       $('#fm').form('clear');
       url = './AssignMedictoPractitioner.php?medicid='+dd_medicid.valueField;
         $('#dg').datagrid('reload');    // reload the current page data
   }



Thanks for your help.

Steve.