I discovered that there is the tag ecma262, which is the same as ecmascript. So I decided to suggest a synonym.
Round One. I tried to suggest ecmascript as a synonym of ecma262. I got "The suggested tag must exist in the system before suggesting it as a synonym!".
Round two. OK, it seems that StackOverflow thinks that ecmascript doesn't exists because it's a synonym of javascript. Then, I tried to add javascript as a synonym of ecma262. But my score in ecma262 tag was 0, so I couldn't (see Remove tag score requirement for suggesting synonyms).
Round three. OK, maybe I don't have ecma262 score, but my javascript score is high. Then, I tried to add ecma262 as a synonym of javascript. I got "Version specific synonyms can only be created by moderators" (see Version specific synonyms can only be created by moderators).
Round four. OK, maybe I don't have any ecma262 score but I could gain it. So I edited added the tag ecma262 to the question Relocating text with js code because my answer has 11 upvotes, and this way gaining 11 ecma262 score. But my ecma262 score was still 0 (see How are tag scores calculated?).
Round five. After some hours, my ecma262 score was updated. And I tried to add javascript as a synonym of ecma262 again. But now I get "Can't create synonym; the 'javascript' tag appears more than 1.25 times the 'ecma262' tag".
So I have lost 5 rounds and I give up because StackOverflow has totally defeated me.