一、JAVASCRIPT：

  1. 代码： 
    var test = function (){
this.str = '',
this.a = function (){
    this.str += "a"
    return this
},
this.b = function(){
    this.str += "b"
    return this
}
this.out = function(){
    console.log(this.str)
}
}
var entity = new test()
entity.a().b().out()
  2. 输出： 
    ab

    二、PHP：

  3. 代码： 
    out .= $a;
    return $this;
}
public function b($b){
    $this->out .= $b;
    return $this;
}
public function say(){
    echo $this->out.PHP_EOL;
}
public function get(){
    return $this->out;
}
}
$single = new single();
$out = $single->a('a')->b('b')->say();
$get = $single->a('a')->b('b')->get();
echo $get;
  4. 输出： 
    ab
abab