function fn1(){
  this
};
fn1(); //this=>window
oDiv.onclick=fn1; //this=>oDiv
oDiv.onclick=function(){
  this //this=>oDiv
  fn1(); //this=>window
}

<div onclick="this.fn1();"></div> //这种行间脚本的写法现在非常罕见

var it=
{
  info:["腾讯","搜狐","新浪","百度"],
  getinfo:function()
  {
    alert(this.info.join(","));
  }
};
it.getinfo();

var it=
{
  info:["腾讯","搜狐","新浪","百度"],
  getinfo:function()
  {
    alert(this.info.join(","));
  }
};
var data=it.getinfo;
data();

var data=function(){
  alert(this.info.join(","));
};
data();

var info=["QQ","sohu","sina","baidu"]
var it=
{
  info:["腾讯","搜狐","新浪","百度"],
  getinfo:function()
  {
    alert(this.info.join(","));
  }
};
var data=it.getinfo;
data();

function test()
{
  alert(this.x);
}
var o={};
o.x=1;
o.t=test;
o.t();

var x=2;
function test()
{
  this.x=1;
}
test();
alert(x);

var x=2;
function test()
{
  this.x=1;
}
var o=new test();
alert(o.x);
alert(x);

var it=
{
  info:["腾讯","搜狐","新浪","百度"],
  getinfo:function()
  {
  function abc(){
    　　alert(this.info.join(","));
  }
  abc();
  }
};
it.getinfo();

var it=
{
  info:["腾讯","搜狐","新浪","百度"],
  getinfo:function()
  {
  var _this=this;
  function abc(){
      alert(_this.info.join(","));
  }
  abc();
  }
};
it.getinfo();