var n1 = Number.prototype.toFixed; var s1 = String.prototype.split; delete Number; delete String; var n2 = (5).toFixed; var s2 = ("foo").split; // Check enumeration doesn't resurrect deleted standard classes for (x in this) {} // Ensure the prototypes are shared. var n3 = (5).toFixed; var s3 = ("foo").split; assertEq(s1, s2); assertEq(s1, s3); assertEq(n1, n2); assertEq(n1, n3);