Stack.contains
<html> <head> <script type="text/javascript"> var djConfig = { baseScriptUri : "js/dojo/", parseOnLoad : true }; </script> <script type="text/javascript" src="js/dojo/dojo/dojo.js"></script> <script> dojo.require("dojox.collections.Stack"); function testIt() { var st = new dojox.collections.Stack(); st.push("A"); st.push("B"); st.push("C"); st.push("D"); alert(st.contains("B")); } </script> </head> <body onLoad="testIt();"> </body> </html>