The ValueChanged event will fire when the value of the dropdown is changed. If the textbox is changed directly, this event will not fire until the control loses focus.
It can be the name of an implemented function or explicit javascript statement(s). If the name of the function is used, then that event handler may contain 3 parameters.
Target Platforms: Windows 10, Windows 8.1, Windows 8, Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2