So today I was working on fixing compatibility issues in Internet Explorer on a new project when I ran into an error like this on IE versions 8 to 10.
SCRIPT1004: Expected ';' File: example.js, Line: 9, Column: 35
And the line it was pointing to looked like this.
var test = 1; //@todo: add new feature
Well it turns out that if conditional compilation (http://msdn.microsoft.com/en-us/library/ie/121hztk3(v=vs.94).aspx) is turned on using
/*@cc_on @*/ in any script. Using the @ symbol anywhere at the start of a comment causes Internet Explorer to throw a syntax error.
The minimum reproducable test case is:
/*@cc_on @*/ var test = 1; //@todo: add new feature
Which can be fixed by putting a space in front of the @ symbol like this.
/*@cc_on @*/ var test = 1; // @todo: add new feature
This becomes an issue in larger codebases where you cannot know if other scripts have turned conditional compilation on at all. As far as I know there isn't a workaround. However you can show a console message warning that conditional compilation is on like this.
/*@if (@_jscript) if ('console' in self && 'log' in console) console.log('Conditional compilation is turned on!'); @end @*/
Keep in mind however that a syntax error caused by the @ symbol will trigger before the above runs.