The sysVar.conversationID system variable stores the conversation ID that is assigned when an EGL program uses a VGUI record to present a web page. A related variable is sysVar.sessionID, which contains an ID that is specific to the web application server session (see sessionID considerations for web transactions).
The conversation ID is unchanged when a program in a web application is invoked by way of a converse statement or by way of a show statement that has a returning clause. A new conversation ID is assigned, however, when the user invokes a program in response to a show statement that has no returning clause.
You can use sysVar.conversationID in these ways:
myVar = sysVar.conversationID;