Much easier approach is to use GREP.

Try this:

app.findGrepPreferences = app.changeGrepPreferences = null;
app.findGrepPreferences.findWhat = "[~m~>~f~|~S~s~<~/~.~3~4~% ]{2,}";
app.changeGrepPreferences.changeTo = "\\s";
app.activeDocument.changeGrep();
app.findGrepPreferences = app.changeGrepPreferences = null;

Hope that helps.

--

Marijan (tomaxxi)

http://tomaxxi.com

Trevor, \s also matches hard returns. It's kind of a stretch to have these included in the usual sense of 'double space'. Marijan's comes from InDesign's own GREP examples ("Multiple Space to Single Space"), and includes regular, non-breaking, en, em, and all thin spaces only.

An annotated version of Learner X's initial version

1   var myDocument = app.activeDocument;
 
2   app.findTextPreferences.findWhat = "NothingEnum.nothing";
3   app.changeTextPreferences.changeTo = "NothingEnum.nothing";
 
4   app.findTextPreferences.findWhat = " ";
5   app.changeTextPreferences.changeTo = " ";
6   app.activeDocument.changeText();
 
7   var myFind = myDocument.findText(true);
 
8   for(i=0; i<myFind.length; i++){
9   //alert(i) /* I think this is the line i need*/
10  }

2,3: NothingEnum.nothing should not be in quotes, it's a numerical constant.

4: Shouldn't there at least be two spaces there?

6: This changes two spaces to one, three spaces to two, etc. -- only once

7: This searches again for the initial query -- any two spaces left?

8 etc. Now this is not 'logical'. It would iterate over the remaining set of two spaces.

I think a logical replacement of 7..10 could be

do
{
  var myFind = myDocument.findText(true);
  if (myFind.length > 0) // found something?
    myDocument.changeText();
} while (myFind.length > 0);

.. but that can be written much more concise, as myDocument.changeText also returns the number of changes, so you can test that right way to see if anything happens (and, consequentially, needs another loop).

Anyway, GREP is a much better way, even if you only and exclusively want to change two spaces to one. Search for "  +" and replace with " ", or, following the dogma "when possible, do not change", search for "(?<= ) +" and replace with "".

Learner X wrote:

 

If i have any doubt i raise my queries in forum. Please help me out  in future. Explain like what you mentioned in the above row.

Well, only when I have the time of course.

If your question is answered, can you mark it as such? That will help people when they have the same question.