-  parent - string or object, id of container, where tree will be initialized, mandatory 
-  name - {string} name which will be assigned to related html input 
-  width - {string} - width of combo ( can be defined in pixels or percents ) 
-  type - type of options used in combo, optional 
-  index - tab index assigned to control, optional 
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- 
- 
- 
-  xml - {string} url of data file ( loadXML- ) 
-  readonly - {boolean} switch to readonly mode( readonly- ) 
 
Options of combo can be defined through items collection
    combo = new dhtmlXCombo({
       parent:"combo_container",
       items:[
            { value:"1", text:"One" },
            { value:"2", text:"Two" },
            { value:"3", text:"Three" }
       ]
    });
Each option can have next attributes
-  value - {string} value of option 
-  label - {string} text which will be shown for the option 
-  css - {string} style string which can be assigned to option 
 
any event can be assigned by using property equal to event name
	combo = new dhtmlXCombo({
		parent:"combo_container",
		onChange:function(){
			alert("I'm changed");	
		}
	});