I don't know if it is the place to ask this. But I will try.
What I need is, for example, if user writes some text in Code Mirror editor like:
a1=Some Text
a11 = Some Child text
and the parser should check if the grammer is correct, and parse it to:
{
'a1' : {
'value' : "Some Text",
'a11' : "some child text"
}
}
Something like this according to the gramme.
So, is there any parser library or something in javascript?
You should be able to use PEG.js to parse the text on the client side. I would also recommend to start off from writing a proper grammar for whatever valid input you are expecting from the user.
This is a bit older, but will give an answer based on a codemirror grammar add-on i have written (as a result of some projects which required syntax-highlight for various custom languages).
One defines a grammar in JSON format for any language (or variation since json grammars can extend other json grammars) and the add-on creates automaticaly a codemirror parser which can include syntax parts and syntax-errors, autocompletion and more
See live example here