Newbie question on FindChangeByList script (REVISED)

Hi...I'm using FindChangeByList (the Javascript version) and I have a question. The default behavior of this script seems to be the following:

1. If text is selected, then run the script on the text

2. Otherwise, run the script on the entire document.

By looking at the script (which I'm pasting below), I can see that the script is intentionally set up this way. I'm totally new to scritping, but by reading the remarks I think these are the relevent lines:

//Something was selected, but it wasn't a text object, so search the document.
     myFindChangeByList(app.documents.item(0));

and

//Nothing was selected, so simply search the document.
   myFindChangeByList(app.documents.item(0));

MY GOAL:  I want to prevent the script running on my entire document by mistake if I mistakenly don't have the Text tool active.

I have a feeling that would be very easy to write, but since I know nothing about scripting, I appeal to this forum. Thanks.

If you need it, the entire script is pasted below. (It's also a standard sample script built into CS4).

//FindChangeByList.jsx
//An InDesign CS4 JavaScript
/*  
@@@BUILDINFO@@@ "FindChangeByList.jsx" 2.0.0.0 10-January-2008
*/
//Loads a series of tab-delimited strings from a text file, then performs a series
//of find/change operations based on the strings read from the file.
//
//The data file is tab-delimited, with carriage returns separating records.
//
//The format of each record in the file is:
//findType<tab>findProperties<tab>changeProperties<tab>findChangeOptions<tab>description
//
//Where:
//<tab> is a tab character
//findType is "text", "grep", or "glyph" (this sets the type of find/change operation to use).
//findProperties is a properties record (as text) of the find preferences.
//changeProperties is a properties record (as text) of the change preferences.
//findChangeOptions is a properties record (as text) of the find/change options.
//description is a description of the find/change operation
//
//Very simple example:
//text {findWhat:"--"} {changeTo:"^_"} {includeFootnotes:true, includeMasterPages:true, includeHiddenLayers:true, wholeWord:false} Find all double dashes and replace with an em dash.
//
//More complex example:
//text {findWhat:"^9^9.^9^9"} {appliedCharacterStyle:"price"} {include footnotes:true, include master pages:true, include hidden layers:true, whole word:false} Find $10.00 to $99.99 and apply the character style "price".
//
//All InDesign search metacharacters are allowed in the "findWhat" and "changeTo" properties for findTextPreferences and changeTextPreferences.
//
//If you enter backslashes in the findWhat property of the findGrepPreferences object, they must be "escaped"
//as shown in the example below:
//
//{findWhat:"\\s+"}
//
//For more on InDesign scripting, go to http://www.adobe.com/products/indesign/scripting/index.html
//or visit the InDesign Scripting User to User forum at http://www.adobeforums.com
//
main();
function main(){
 var myObject;
 //Make certain that user interaction (display of dialogs, etc.) is turned on.
 app.scriptPreferences.userInteractionLevel = UserInteractionLevels.interactWithAll;
 if(app.documents.length > 0){
  if(app.selection.length > 0){
   switch(app.selection[0].constructor.name){
    case "InsertionPoint":
    case "Character":
    case "Word":
    case "TextStyleRange":
    case "Line":
    case "Paragraph":
    case "TextColumn":
    case "Text":
    case "Cell":
    case "Column":
    case "Row":
    case "Table":
     myDisplayDialog();
     break;
    default:
     //Something was selected, but it wasn't a text object, so search the document.
     myFindChangeByList(app.documents.item(0));
   }
  }
  else{
   //Nothing was selected, so simply search the document.
   myFindChangeByList(app.documents.item(0));
  }
 }
 else{
  alert("No documents are open. Please open a document and try again.");
 }
}
function myDisplayDialog(){
 var myObject;
 var myDialog = app.dialogs.add({name:"FindChangeByList"});
 with(myDialog.dialogColumns.add()){
  with(dialogRows.add()){
   with(dialogColumns.add()){
    staticTexts.add({staticLabel:"Search Range:"});
   }
   var myRangeButtons = radiobuttonGroups.add();
   with(myRangeButtons){
    radiobuttonControls.add({staticLabel:"Document"});
    radiobuttonControls.add({staticLabel:"Selected Story", checkedState:true});
    if(app.selection[0].contents != ""){
     radiobuttonControls.add({staticLabel:"Selection", checkedState:true});
    }
   }   
  }
 }
 var myResult = myDialog.show();
 if(myResult == true){
  switch(myRangeButtons.selectedButton){
   case 0:
    myObject = app.documents.item(0);
    break;
   case 1:
    myObject = app.selection[0].parentStory;
    break;
   case 2:
    myObject = app.selection[0];
    break;
  }
  myDialog.destroy();
  myFindChangeByList(myObject);
 }
 else{
  myDialog.destroy();
 }
}
function myFindChangeByList(myObject){
 var myScriptFileName, myFindChangeFile, myFindChangeFileName, myScriptFile, myResult;
 var myFindChangeArray, myFindPreferences, myChangePreferences, myFindLimit, myStory;
 var myStartCharacter, myEndCharacter;
 var myFindChangeFile = myFindFile("/FindChangeSupport/FindChangeList.txt")
 if(myFindChangeFile != null){
  myFindChangeFile = File(myFindChangeFile);
  var myResult = myFindChangeFile.open("r", undefined, undefined);
  if(myResult == true){
   //Loop through the find/change operations.
   do{
    myLine = myFindChangeFile.readln();
    //Ignore comment lines and blank lines.
    if((myLine.substring(0,4)=="text")||(myLine.substring(0,4)=="grep")||(myLine.substring(0,5)=="glyph")){
     myFindChangeArray = myLine.split("\t");
     //The first field in the line is the findType string.
     myFindType = myFindChangeArray[0];
     //The second field in the line is the FindPreferences string.
     myFindPreferences = myFindChangeArray[1];
     //The second field in the line is the ChangePreferences string.
     myChangePreferences = myFindChangeArray[2];
     //The fourth field is the range--used only by text find/change.
     myFindChangeOptions = myFindChangeArray[3];
     switch(myFindType){
      case "text":
       myFindText(myObject, myFindPreferences, myChangePreferences, myFindChangeOptions);
       break;
      case "grep":
       myFindGrep(myObject, myFindPreferences, myChangePreferences, myFindChangeOptions);
       break;
      case "glyph":
       myFindGlyph(myObject, myFindPreferences, myChangePreferences, myFindChangeOptions);
       break;
     }
    }
   } while(myFindChangeFile.eof == false);
   myFindChangeFile.close();
  }
 }
}
function myFindText(myObject, myFindPreferences, myChangePreferences, myFindChangeOptions){
 //Reset the find/change preferences before each search.
 app.changeTextPreferences = NothingEnum.nothing;
 app.findTextPreferences = NothingEnum.nothing;
 var myString = "app.findTextPreferences.properties = "+ myFindPreferences + ";";
 myString += "app.changeTextPreferences.properties = " + myChangePreferences + ";";
 myString += "app.findChangeTextOptions.properties = " + myFindChangeOptions + ";";
 app.doScript(myString, ScriptLanguage.javascript);
 myFoundItems = myObject.changeText();
 //Reset the find/change preferences after each search.
 app.changeTextPreferences = NothingEnum.nothing;
 app.findTextPreferences = NothingEnum.nothing;
}
function myFindGrep(myObject, myFindPreferences, myChangePreferences, myFindChangeOptions){
 //Reset the find/change grep preferences before each search.
 app.changeGrepPreferences = NothingEnum.nothing;
 app.findGrepPreferences = NothingEnum.nothing;
 var myString = "app.findGrepPreferences.properties = "+ myFindPreferences + ";";
 myString += "app.changeGrepPreferences.properties = " + myChangePreferences + ";";
 myString += "app.findChangeGrepOptions.properties = " + myFindChangeOptions + ";";
 app.doScript(myString, ScriptLanguage.javascript);
 var myFoundItems = myObject.changeGrep();
 //Reset the find/change grep preferences after each search.
 app.changeGrepPreferences = NothingEnum.nothing;
 app.findGrepPreferences = NothingEnum.nothing;
}
function myFindGlyph(myObject, myFindPreferences, myChangePreferences, myFindChangeOptions){
 //Reset the find/change glyph preferences before each search.
 app.changeGlyphPreferences = NothingEnum.nothing;
 app.findGlyphPreferences = NothingEnum.nothing;
 var myString = "app.findGlyphPreferences.properties = "+ myFindPreferences + ";";
 myString += "app.changeGlyphPreferences.properties = " + myChangePreferences + ";";
 myString += "app.findChangeGlyphOptions.properties = " + myFindChangeOptions + ";";
 app.doScript(myString, ScriptLanguage.javascript);
 var myFoundItems = myObject.changeGlyph();
 //Reset the find/change glyph preferences after each search.
 app.changeGlyphPreferences = NothingEnum.nothing;
 app.findGlyphPreferences = NothingEnum.nothing;
}
function myFindFile(myFilePath){
 var myScriptFile = myGetScriptPath();
 var myScriptFile = File(myScriptFile);
 var myScriptFolder = myScriptFile.path;
 myFilePath = myScriptFolder + myFilePath;
 if(File(myFilePath).exists == false){
  //Display a dialog.
  myFilePath = File.openDialog("Choose the file containing your find/change list");
 }
 return myFilePath;
}
function myGetScriptPath(){
 try{
  myFile = app.activeScript;
 }
 catch(myError){
  myFile = myError.fileName;
 }
 return myFile;
}

Message was edited by: JoJo Jenkins. Proper script formatting was used and the question was revised and made more concise.