zohoEstimatePlugin.js

// ==UserScript==
// @name         Zoho Estimate Plugin
// @namespace    http://tampermonkey.net/
// @version      0.1
// @description  Add button for converting Zoho estimates to purchase and sales orders.
// @author       You
// @include      https://books.zoho.eu/app
// @grant        GM_log
// ==/UserScript==

(function() {
  'use strict';
  
  function createLinkElement(text, href) {
    var a = document.createElement('a');
    var linkText = document.createTextNode(text);
    a.appendChild(linkText);
    a.href = href;
    a.className = "btn btn-default";
    a.target = "_blank";
    return a;
  }
  
  function perform(waitTime) {
    waitTime = waitTime || 100;
    
    setTimeout(function() {
      var match = location.hash.match(/#\/quotes\/(\d+)\?/);
      
      if (!match) {
        return;
      }
      
      var estimateId = match[1];
      var replacedElement = document.querySelector(".content-column .btn-toolbar > button");
      
      if (!replacedElement) {
        perform(waitTime * 2);
        return;
      }
      
      var linkHref = "https://portal.steelscout.com/zoho?enquiryId=" + estimateId;
      var newLinkElement = createLinkElement("Convert to Purchase Orders", linkHref);
      
      replacedElement.parentNode.replaceChild(newLinkElement, replacedElement);
    }, waitTime);
  }
  
  window.addEventListener("popstate", perform);
  perform();
})();