Strange keywords conflict between flash and IE

I have a small SWF file used to play the sound. After adding it to HTML, it can be played normally in Firefox/chrome, but IE8 only prompts

 
Message: the object does not support this attribute or method line: 48 characters: 3 code: 0uri :....
 

I checked 48 in the file, which is an HTML Tag and cannot contain any conflict. Then, I checked the JS files one by one and found no problems. Finally, I suspect that the SWF file causes IE to report an error. Therefore, I deleted the SWF embedded in HTML and F5 and IE to run normally. Therefore, it must be as3. Which of the following conflicts between as3 and JS?

 
Flash. External. externalinterface
 

Method. View the three methods open to JS:

 
Externalinterface. addcallback ('Play', Player. Play); externalinterface. addcallback ('Switch', Con. Change); externalinterface. addcallback ('Close', Player. Stop );
 

Swtich is indeed a reserved word of JS. If it is changed, an error is still returned.

Where is the problem? Is play or close a reserved word or reserved word? Apparently not. So I checked other codes in as3 and found no problems.

Finally, take a try and change the three open methods one by one.

 
Externalinterface. addcallback ('Vplay', Player. Play); externalinterface. addcallback ('Vswitch', Con. Change); externalinterface. addcallback ('Vclose', Player. Stop );
 

Flash exports SWF and runs again. The result is that IE is normal. I cannot figure out why.