Question

I know this might look silly, but I still don’t know why this happens (for a couple times already.)

alert(
"WWVhaCA6RCwgYSBsb3Qgb2YgcGVvcGxlIGRvbid0IGtub3cgdGhhdCB0aGlzIGlzIGVuY29kZWQgOkQ=" == 
"WWVhaCA6RCwgYSBsb3Qgb2YgcGVvcGxlIGRvbid0IGtub3cgdGhhdCB0aGlzIGlzIGVuY29kZWQgOkQ=")​

Demo: http://jsfiddle.net/DerekL/b38Cn/

It should return true but instead it returns false. I looked through each character (in Notepad because it uses a monospace font), and they are exactly the same.

Answer 1

As @ElliotBonneville says, there is a hidden unicode character in the text. It is visible by pasting the strings into command prompt:

Notice the ? at the end of the first string.