# Simple Script Function

This is an example of a [script function](../script_functions) that displays the name of the largest file in the current folder, and gives you the option to select it.

To use this function you would:

* [Create a new toolbar button](../../customize/creating_your_own_buttons) or hotkey and [edit](../../customize/creating_your_own_buttons/editing_the_toolbar) it
* Click the **Advanced** button in the [command editor](../../customize/creating_your_own_buttons/command_editor) to switch to the [advanced command editor](../../customize/creating_your_own_buttons/command_editor/advanced_command_editor)
*   Set the **Function** drop-down to **Script Function**

    // Set the script type to JScript to use this script. // main script entry point. clickData is a ClickData object. function OnClick(clickData) { // Initialise a variable to keep track of the largest file. largestFile = null;

    ```
      // Create an enumerator object that will let us easily enumerate the files in the current tab.
      // clickData.func is a Func object.
      // func.sourcetab is a Tab object.
      // sourcetab.files is a collection of Item objects.
      enumFiles = new Enumerator(clickData.func.sourcetab.files);

      // Enumerate the files in the tab.
      enumFiles.moveFirst();
      while (enumFiles.atEnd() == false)
      {
          // If this is the largest file encountered so far, keep track of it.
          // The file size is obtained from the Item object via its size property.
          // We use the FileSize object's cy property as this makes it easier to compare
          // two sizes numerically.
          if (largestFile == null || largestFile.size.cy < enumFiles.item().size.cy)
              largestFile = enumFiles.item();
          enumFiles.moveNext();
      }

      // Create a Dialog object to display the results.
      dlg = clickData.func.Dlg;
      if (largestFile == null)
      {
          // There were no files found, so show a warning message.
          dlg.message = "There are no files in this folder!";
          dlg.buttons = "OK";
          dlg.icon = "warn";
      }
      else
      {
          // Build the info message to report on the largest file.
          // The dialog will have two buttons, giving the user the option to select the file.
          dlg.message = "The largest file is '" + largestFile.name + "' - " + largestFile.size.fmt;
          dlg.buttons = "Select It|Cancel";
          dlg.icon = "info";
      }

      dlg.title = "Largest File Finder";
      
      // Display the dialog. if the user clicks the "Select It" button it will return 1.
      if (dlg.Show() == 1)
      {
          // Initialise and run the Select command to select the largest file.
          // This makes use of the Command object provided to the button via clickData.func.
          clickData.func.command.ClearFiles();
          clickData.func.command.AddFile(largestFile);
          clickData.func.command.RunCommand("Select FROMSCRIPT DESELECTNOMATCH MAKEVISIBLE");
      }
      else
      {
          // Not selecting a file, so make sure anything already selected is unaffected.
          clickData.func.command.deselect = false;
      }
    ```

    }
