How to limit the JPG file size within 300 Kb?

Bonjour

//SauveWebJPG_Poids.jsx //Sauve l image a un poids inferieur a 300 ko // R : //Il faut que le dernier format d enreregistrement soit sur Images //et non sur HTML et images var docRef = activeDocument; var outputFolder = docRef.path; var blog = new Folder(outputFolder  +"/blog"); blog.create(); var outputFolder= new Folder(outputFolder +"/blog"); Nom = docRef.name; NamesaveRef = new File( outputFolder + "/" + Nom ); var NewfileRef = new File( NamesaveRef ) // Test du POIDS var poidsMax =  300000; // pour 300 ko maximum var qualit = 100; var x = 1;//pour accelerer le script mettre x = 5 EnregWeb(NewfileRef, qualit);      while (NewfileRef.length > poidsMax ) {         qualit = qualit - x;         NewfileRef = new File( NewfileRef );            NewfileRef.remove();         EnregWeb(NewfileRef, qualit);             if (qualit<=0)             {         alert("La taille de l'image est telle qu'elle ne peut être sauvegardée avec un poids de 300 ko.");             break                        } } var poidsFichier = NewfileRef.length /1000; poidsFichier = Math.round(poidsFichier); // fermer l original sans enregistrer activeDocument.close(SaveOptions.DONOTSAVECHANGES); function EnregWeb(filename, qualit) {       var options = new ExportOptionsSaveForWeb();       options.quality = qualit;   // Start with highest quality (biggest file).       options.format = SaveDocumentType.SGIRGB//JPEG;   // Or it'll default to GIF.       docRef.exportDocument(File( filename), ExportType.SAVEFORWEB, options); }

You can try this

But this risk to be a little long................

I don't think that can be done via scripting. You normally have to set the quality, and PS then calculates what the file size will be. It doesn't work even without scripting to set the file size first.