HTMLItemComboBox is a custom web control that is similar to ASP ComboBox but instead only having to define the items as text; in the HTMLItemComboBox you can use any HTML item as input. That means for example you could define a ComboBox of images, italic words and any other HTML items you wish. Therefore you can have a ComboBox that contains different type of items. Each item in the ComboBox has a value attribute which is different from what we see in the ComboBox. Therefore for defining every item for the HTMLItemComboBox you should define a pair of value and key, which key is what we see in the combobox and value is a velue behind each item. So it is very important that everytime an item is selected in the HTMLItemComboBox the value is returned.