In mozilla javascript Array.prototype.every.call works on strings converting the string to an array of characters. In AS3 the call returns true without calling the function. Changing the code from a string to an array of characters works correctly. This code reproduces the problem: every1.as: function isLetter(character) { print(character); return (character >= "a" && character <= "z"); } // var str=['a','b','c','1','2','3']; works var str="abc123"; // in avmplus returns true print(Array.prototype.every.call(str,isLetter)); Reproduction: 1. running with mozilla's js.exe works: js every1.as returns a,b,c,1,false as expected 2. asc every1.as 3. avmplus every1.abc returns: true Actual Results: avmplus every1.abc: true Expected Results: avmplus every1.abc: a b c 1 false Workaround: convert the string to an array of characters Transferred Comments: BugDB Migration - Mon Jun 04 12:32:53 CDT 2007 [dschaffer 9/5/06] Entered Bug. [cnuuja 9/5/06] This is because Spidermonkey implements an optional feature (i.e. not in the ECMA spec) where by strings can be accessed ala arrays: var s = "abcd" print(s[1]) // "b" for spidermonkey, error for us. This is an enhancement request for fp10 to support index properties for Strings ala Spidermonkey. The fact that they use this feature in the examples in the Documentation should perhaps raise this feature's priority for us. JIRA Migration Admin - Mon Jun 04 12:32:53 CDT 2007 Milestone ID = 1378 Milestone = FP 10 - Code Complete Build ID = 21378 Build = AVMPLUS_1_0_0_d659 Fix Build ID = null Fix Build = null JIRA Migration Admin - Mon Jun 04 12:32:53 CDT 2007 Move from BugDB issue number 183657 Trevor Baker - Tue Jan 27 14:54:40 CST 2009 back to internal review for reprioritization This bug transferred from: http://bugs.adobe.com/jira/browse/ASC-2276