In IE7, why does Javascript fail to use index strings? -Php Tutorial

In IE7, why does Javascript fail to use index strings? The problem code is described as follows:
Function filter_str (str ){
Var res = "";
For (var I = 0; I
Var c = str. charCodeAt (I );
If (c> 32 & c! = 127 & c! = 39 ){
Res + = str [I]. toString (); // when IE7 or IE7 is the kernel, an error is reported.
}
}
Return res;
}

Do you know what the rule is?

Reply to discussion (solution)

IE (JScript) complies with earlier JavaScript conventions
Therefore, strings cannot be operated in array mode.
Str [I]. toString ()
Ying writing
Str. charAt (I)

IE (JScript) complies with earlier JavaScript conventions
Therefore, strings cannot be operated in array mode.
Str [I]. toString ()
Ying writing
Str. charAt (I)

Learning...

What is the difference between the early JavaScript conventions and the current JavaScript conventions? Where can I find out? are there any relevant documents?


Thank you.

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