Javascript: remove trailing spaces only

Can anyone help me on how to remove trailing spaces in JavaScript. I want to keep the leading spaces as is and only remove trailing spaces.<br/> EG: ' test ' becomes ' test'. Seems like pretty simple but I can't figure it out.

PS: I am pretty sure I can't be the first one to ask this but I can't find an answer in SO. Also, I am looking for JavaScript solution. I am not using jQuery.

Update 2019

String trim methods have been added to ECMAScript spec in 2019 with wide browser support

• String.trim()
• String.trimStart()
• String.trimEnd()

You can use like this:

" test ".trimEnd() // " test"

Further Reading

• tc39 proposal - String.prototype.{trimStart,trimEnd}