Get selected value from combo box?

I using  below sample code for using the combo box . How do i assign the user selected value from combo box as value to a variable "MyVariable" .

<ComboBox id="combobox" items="{/Customers}" >

  <items>

    <core:Item key="{CustomerID}" text="{CompanyName}"/>

  </items>

</ComboBox>

var oModel = new sap.ui.model.odata.ODataModel("http://services.odata.org/Northwind/Northwind.svc", true);

  this.getView().setModel(oModel);

oFilter = new sap.ui.model.Filter("ContactTitle", sap.ui.model.FilterOperator.EQ, "Owner");

this.getView().byId("combobox").getBinding("items").filter(oFilter);