google search change page with arrow kets(left/right)

googleSearchChangePageWithArrow.js

/*
在 Google 頁面使用方向鍵切換上一頁、下一頁
Change result page with Arrow keys(left/right) on google search pages.

請搭配以下環境參數和 Personalized Web 參數使用
env: chrome with extension "Personalized Web" ( https://chrome.google.com/webstore/detail/personalized-web/plcnnpdmhobdfbponjpedobekiogmbco )
setting of Personalized Web:
  Match URLs: ^https://www.google.com/search.*
  Add JavaScript: add the following JS
*/

var _detectspecialkeys = function (e){
  var evtobj=window.event? event : e;
  var code = e.keyCode;
  if (e.charCode && code == 0)
    code = evtobj.charCode;
 
  var _nav= document.getElementById('nav');
  var _tds=_nav.getElementsByTagName('td');
  var _cur=false;
  for(var i=0;i<_tds.length;i++){
    if(!_cur && _tds[i].className==='cur' )
      _cur = i ;
  }
  switch(code) {
    case 37:  //left
    if(_cur!==1)
      window.location.href=_tds[_cur-1].getElementsByTagName('a')[0].getAttribute('href',0);
    break;
    case 39:  //right
      window.location.href=_tds[_cur+1].getElementsByTagName('a')[0].getAttribute('href',0);
    break;
  }
}
// change:
//add detector: if search textbox is focused, stop the arrow key handler
//加入判斷，焦點在搜尋框時，取消方向鍵作用
var _gsfi=document.getElementsByClassName('gsfi');
console.log('length' + _gsfi.length);
for(var i=0;i<_gsfi.length;i++){
  if(_gsfi[i].tagName==='INPUT'){
    var elem= _gsfi[i];
    elem.onfocus=function(e) {
      window.onkeydown=null;
    };
    elem.onblur=function(e) {
      window.onkeydown=_detectspecialkeys;
    };
  }
}

window.onkeydown = _detectspecialkeys;