Question

I have a string “#letme.doit.now .emiter #another.test #plus.test.”
I need to find all dots that has something after, which are in those parts that starts with # and don’t have white spaces.
Actually the match has to hold dot 1, 2, 4 and 5. All other dots don’t have to be there in the match.

Answer 1

This will find and escape the dots according to the requirements:

Demo: http://jsfiddle.net/q9hLQ/

var string = "#letme.doit.now .emiter #another.test #plus.test.";
string = string.replace(/#\S+/g, function(full_match) {
    return full_match.replace(/\.(?!$)/g, '\\.');
});
// Output: #letme\.doit\.now .emiter #another\.test #plus\.test.

1. Find each consecutive # + non-whitespace characters.
2. Inside these matches, replace all dots, except for the dot at the end, with a backslash+dot.