Script for switching master pages

Question

Would it be possible to write a script to do this: Replace one master page with another whenever a certain paragraph style appears? I'm looking for a quick way to replace my A Master (with running header and page number) with the None Master on pages where new chapters begin.
Clark

Answer 1

here you go (it also creates sections)
var ProgressBar = function(/*str*/title){
     var w = new Window('palette', ' '+title, {x:0, y:0, width:340, height:60}),
          pb = w.add('progressbar', {x:20, y:12, width:300, height:12}, 0, 100),
          st = w.add('statictext', {x:10, y:36, width:320, height:20}, '');
     st.justify = 'center';
     w.center();
     this.reset = function(msg,maxValue)
          st.text = msg;
          pb.value = 0;
          pb.maxvalue = maxValue||0;
          pb.visible = !!maxValue;
          w.show();
     this.hit = function() {++pb.value;};
     this.hide = function() {w.hide();};
     this.close = function() {w.close();};
function main(){
var doc = app.documents.item(0);
// Create a list of paragraph styles
var list_of_paragraph_styles = [];
var all_paragraph_styles = [];
var list_of_masters_names=[];
var list_of_masters=[];
for (var i= 0; i<doc.masterSpreads.length;i++){
    list_of_masters_names.push(doc.masterSpreads[i].name);
    list_of_masters.push(doc.masterSpreads[i]);
list_of_masters_names.push("undefined");
doc.paragraphStyles.everyItem().name;
for(var i = 0; i < doc.paragraphStyles.length; i++) {
           list_of_paragraph_styles.push(doc.paragraphStyles[i].name);
           all_paragraph_styles.push(doc.paragraphStyles[i]);
for(var i = 0; i < doc.paragraphStyleGroups.length; i++) {
          for(b = 0; b < doc.paragraphStyleGroups[i].paragraphStyles.length; b++) {
                    list_of_paragraph_styles.push(doc.paragraphStyleGroups[i].name+"->"+doc.paragraphStyleGroups[i].paragraphStyles[b].name);
                    all_paragraph_styles.push(doc.paragraphStyleGroups[i].paragraphStyles[b]);
// Make the dialog box for selecting the paragraph styles
var the_dialog = app.dialogs.add({name:"Section start at paragraph style:"});
with(the_dialog.dialogColumns.add()){
          with(dialogRows.add()){
                    staticTexts.add({staticLabel:"Find:"});
          with(borderPanels.add()){
                    var find_first_paragraph = dropdowns.add({stringList:list_of_paragraph_styles, selectedIndex:0});
with(dialogRows.add()){
                    staticTexts.add({staticLabel:"Apply Master:"});
          with(borderPanels.add()){
                    var change_master = dropdowns.add({stringList:list_of_masters_names, selectedIndex:0});
                    staticTexts.add({staticLabel:"Select \"undefined\" not to change"});
the_dialog.show();
// Define paragraph styles
var myParagraph = all_paragraph_styles[find_first_paragraph.selectedIndex];
var myMaster=(list_of_masters_names[change_master.selectedIndex]!="undefined")?list_of_masters[change_master.selectedIndex]:null;
app.findChangeGrepOptions.includeFootnotes = false;
app.findChangeGrepOptions.includeHiddenLayers = false;
app.findChangeGrepOptions.includeLockedLayersForFind = false;
app.findChangeGrepOptions.includeLockedStoriesForFind = false;
app.findChangeGrepOptions.includeMasterPages = false;
app.findGrepPreferences = NothingEnum.nothing;
app.findGrepPreferences.appliedParagraphStyle = myParagraph;
var myFound=doc.findGrep();
var i=myFound.length;
var pBar = new ProgressBar("Sectioning");
     pBar.reset("Rabdare...", i);
while (i--)
        pBar.hit();
        if (myFound[i].parentTextFrames[0].parent.constructor.name=="Character"){
            var myPage=myFound[i].parentTextFrames[0].parent.parentTextFrames[0].parentPage;}
        else{
     var myPage=myFound[i].parentTextFrames[0].parentPage;}
     var mySection;
     if (myPage.appliedSection.pageStart==myPage){mySection=myPage.appliedSection;}
     else{
     doc.sections.add(myPage,{pageNumberStart:1})};
    // mySection.pageStart=myPage;
     //mySection.pageNumberStart=1;
     if (myMaster) {myPage.appliedMaster=myMaster};
alert("Acum e gata!!");
app.doScript('main()',undefined,undefined,UndoModes.entireScript,'AutoSections');
//main();