extjs - Ext JS Dependent combo box -

i new extjs, , trying implement following functionality:

i have 2 select drop down menus, transformed using extjs. how can make sure if value in 1 combo box selected, other value should set default value?

thanks.

edited: code till now:

ext.onready(function(){   var converted = new ext.form.combobox({       typeahead: true,      triggeraction: 'all',      transform:'id_select1',      width:600,      forceselection:true,      emptytext:'select'   });   var convertedcdr = new ext.form.combobox({      typeahead: true,      triggeraction: 'all',      transform:'id_select2',      width:600,      forceselection:true,      emptytext:'select'  });  }); 

i using coldfusion query database , populate drop down menus:

<cfquery name="getdata1" datasource="abc">    select * table1 </cfquery>  <cfquery name="getdata2" datasource="abc">    select * table2 </cfquery>  <select name="select1" id="select1">   <cfoutput query="getdata1">        <option value="#getdata1.id#">#getdata1.name#</option>   </cfoutput> </select>   <select name="select2" id="select1">   <cfoutput query="getdata2">        <option value="#getdata2.id#">#getdata2.name#</option>   </cfoutput> </select> 

edited - haven't used cfm... you'll need figure out how load cf using data stores use technique.

you need add listener select event on combo:

xtype: 'combo', id   : 'firstcomboid', listeners: {   select: function(combo,  record,  index ) {     var selval = ext.getcmp('firstcomboid').getvalue();     var secondcombo = ext.getcmp('secondcomboid');     secondcombo.store.reload({params: {yourparametername: selval}}); } 

basically doing following here:

1. get value selected in first combo
2. get reference second combo's data store
3. reload store of second combo box using selected value first combo