Open Lookup window in CRM V9.0

XRM.Utlity

Property Name	Type	Required	Description
allowMultiSelect	Boolean	No	Indicates whether the lookup allows more than one item to be selected.
defaultEntityType	String	No	The default entity type to use.
defaultViewId	String	No	The default view to use.
entityTypes	Array	No	The entity types to display.
showBarcodeScanner	Boolean	No	Indicates whether the lookup control should show the barcode scanner in mobile clients.
viewIds	Array	No	The views to be available in the view picker. Only system views are supported.

Xrm.Utility.lookupObjects(lookupOptions).then(successCallback, cancelCallback)

var lookupOptions =new Object();
lookupOptions.allowMultiSelect=false
lookupOptions.defaultEntityType='contact'
var arr=new Array()
arr.push('A2D479C5-53E3-4C69-ADDD-802327E67A0D')
lookupOptions.viewIds=arr

lookupOptions.defaultViewId='A2D479C5-53E3-4C69-ADDD-802327E67A0D'

var arr2=new Array();
arr2.push('contact');
lookupOptions.allowMultiSelect=false;
lookupOptions.entityTypes=arr2;
Xrm.Utility.lookupObjects(lookupOptions).then(successCallback, cancelCallback)
function successCallback(objResult){debugger;

}
function cancelCallback(){}