Make Background layer and top layer visible

Thanks a lot Pedro Cortez Marques,JJMack Pedro Cortez Marques

But currently it processing all the layer sets in the active document if it is possible to unprocess a particular named group

eg; in the document there is an layer group called Masks above this masks group all my actual layersets are there so basically i need to process all the groups above the masks group and not the layer groups below Masks layergroups.

Quick Top and Bottom of a documents visibility ON will not change the visibility state of layes within top and botton  layer Groups.

var layers = activeDocument.layers;

layers[0].visible=true; // Top Layer or Layer Group

layers[layers.length-1].visible=true;    // Background Layer or Bottom Layer or Group

Hi. I hope it helps.

#target photoshop; 
if (app.documents.length > 0) { 
    var thedoc = app.activeDocument; 
    // getting the name and location; 
    var docName = thedoc.name; 
    if (docName.indexOf(".") != -1) {
        var basename = docName.match(/(.*)\.[^\.]+$/)[1];
    } else {
        var basename = docName;
    }; 
    // getting the location, if unsaved save to desktop; 
    try {
        var docPath = thedoc.path} 
    catch (e) {
        var docPath = "~/Desktop"
    }; 
    //
    var layerSets_ = app.activeDocument.layerSets;
    for (var a =0; a < layerSets_.length; a++) {
        // turn all layerSets invisible
        for (var b =0; b < layerSets_.length; b++) {
            layerSets_.visible = false;
        }
        layerSets_.visible = true;
        // jpg options; 
        var jpegOptions = new JPEGSaveOptions(); 
        jpegOptions.quality = 12; 
        jpegOptions.embedColorProfile = true; 
        jpegOptions.matte = MatteType.NONE; 
        //save jpg in layerset name: 
        thedoc.saveAs(new File(Folder.desktop + '/backup/'+layerSets_.name+'.jpg'),jpegOptions,true); 
        //thanks to xbytor;
    }
};