jisho-no-focus.user.js

// ==UserScript==
// @name         Jisho.org no focus unless empty
// @namespace    https://myconan.net
// @version      0.0.1
// @description  Don't focus input box unless empty
// @author       nanaya
// @match        https://jisho.org/*
// @grant        none
// ==/UserScript==

;(function () {
  'use strict'

  var inputBox = document.getElementById('keyword')
  var restore = function () {
    inputBox.disabled = false
    if (inputBox.value === '') {
      inputBox.focus()
    }
  }

  if (inputBox != null) {
    inputBox.disabled = true
    setTimeout(restore, 1)
  }
}).call()