Note: After saving, you have to bypass your browser's cache to see the changes. Google Chrome, Firefox, Microsoft Edge and Safari: Hold down the ⇧ Shift key and click the Reload toolbar button. For details and instructions about other browsers, see Wikipedia:Bypass your cache.
// [[User:Animum/reset.js]] by Animum
// To include this in your monobook, add the following line to it (minus the "//"):
// importScript('User:Animum/reset.js');

importScript('User:Animum/urlparameters.js');
importScript('User:Voice of All/Addtabs/monobook.js');

function resetSandbox() {
  if(typeof UrlParameters === 'undefined') return;
  if(UrlParameters["sandboxreset"] == 1 && mw.config.get('wgPageName') == "Wikipedia:Sandbox" && UrlParameters["action"] == "edit") {
    document.forms["editform"].elements["wpTextbox1"].value = "\{\{Please leave this line alone (sandbox heading)\}\}\n<!-- Hello! Feel free to try your formatting and editing skills below this line\. As this page is for editing experiments, this page will automatically be cleaned every 12 hours. -->"; //Add the base text for the sandbox
    document.forms["editform"].elements["wpSummary"].value = "[[User:Animum/reset.js|JS EDIT]]: Reset the Sandbox"; //Make a descriptive edit summary
    document.forms["editform"].elements["wpMinoredit"].checked = true; //Make it a minor edit
    if(UrlParameters["indirect"] == 1) { //If you've clicked on the toolbox link
      window.setTimeout(function() { document.forms["editform"].elements["wpDiff"].click(); }, 200); //Load the diff if you are resetting it per the toolbox link
      var save = confirm("Save? (click \"OK\" to save; \"cancel\" to abort)"); // Do you want to make these changes?
      if(save == true) { 
        window.setTimeout(function() { document.forms["editform"].elements["wpSave"].click(); }, 200); //Submit it!
      } else { location.href = mw.config.get('wgArticlePath').replace(/\$1/g, "Wikipedia:Sandbox"); } // Go back two pages if you don't want to save it
    } else {
    window.setTimeout(function() { document.forms["editform"].elements["wpSave"].click(); }, 200); //Submit it! 
    }
  }
}
 
$(function () {
    if(mw.config.get('wgPageName') == "Wikipedia:Sandbox") // If the page you are viewing is the sandbox
      { mw.util.addPortletLink('p-cactions', mw.config.get('wgScript') + "?title=Wikipedia:Sandbox&action=edit&sandboxreset=1", 'reset', 'ca-reset', "Reset the Sandbox"); }
    if(typeof addToolboxLink !== 'undefined' && mw.config.get('wgPageName') != "Wikipedia:Sandbox") // If the page you are viewing is NOT the sandbox 
      { addToolboxLink(mw.config.get('wgScript') + "?title=Wikipedia:Sandbox&action=edit&sandboxreset=1&indirect=1", 'Reset the Sandbox', '', '', ''); }
});

$(resetSandbox);