I have been developing with ExtJS for nearly a year, and I have encountered many strange problems. The most impressive one is the display problem of ExtJS in IE. Since most of the development process uses Chrome for debugging and rarely debugs in IE (now both have to be taken into consideration), the page in IE finally failed to load normally. It was embarrassing at the time. When I saw the error reported by IE, I thought Crying, I don’t even have the stack information of the error (IE is really bad at this), so I can’t start. After trying many methods, I finally found that the cause of this problem (more than 90% possibility) is that there is an extra English comma ',' in the js array, and this is no problem in Chrome and Firefox. , as shown in the following code: