code: function(e) {
  	        if (e['arguments'] && e.stack) {
  	            return 'chrome';
  	        } else if (e.stack && e.sourceURL) {
  	            return 'safari';
  	        } else if (e.stack && e.number) {
  	            return 'ie';
  	        } else if (typeof e.message === 'string' && typeof window !== 'undefined' && window.opera) {
  	            // e.message.indexOf("Backtrace:") > -1 -> opera
  	            // !e.stacktrace -> opera
  	            if (!e.stacktrace) {
  	                return 'opera9'; // use e.message
  	            }
  	            // 'opera#sourceloc' in e -> opera9, opera10a
  	            if (e.message.indexOf('\n') > -1 && e.message.split('\n').length > e.stacktrace.split('\n').length) {
  	                return 'opera9'; // use e.message
  	            }
  	            // e.stacktrace && !e.stack -> opera10a
  	            if (!e.stack) {
  	                return 'opera10a'; // use e.stacktrace
  	            }
  	            // e.stacktrace && e.stack -> opera10b
  	            if (e.stacktrace.indexOf("called from line") < 0) {
  	                return 'opera10b'; // use e.stacktrace, format differs from 'opera10a'
  	            }
  	            // e.stacktrace && e.stack -> opera11
  	            return 'opera11'; // use e.stacktrace, format differs from 'opera10a', 'opera10b'
  	        } else if (e.stack && !e.fileName) {
  	            // Chrome 27 does not have e.arguments as earlier versions,
  	            // but still does not have e.fileName as Firefox
  	            return 'chrome';
  	        } else if (e.stack) {
  	            return 'firefox';
  	        }
  	        return 'other';
  	    }
docs: Mode could differ for different exception, e.g.
  exceptions in Chrome may or may not have arguments or stack.
  
  @return {String} mode of operation for the exception