<p id="scope3" style="color:red"></p>

var pscope3 = document.getElementById('scope3');
        function scope3() {
            for(var i=0; i<10; i++){ 
            }
            echo(pscope3,  i);
        }
        scope3();

function scope3() {
            var i;
            for(i=0; i<10; i++){ 
            }
            echo(pscope3,  i);
        }

function anonymous() {
            var position = 'in anonymous';
            (function(){
                for(var i=0; i<10; i++){ 
                }
                echo(pscope3, position);//打印显示"in anonymous"
            })();
            //pscope3.innerHTML += i;//报错
        }
        anonymous();

function capture() {
            var ex = 'in capture';
            try{  
                i;
            }catch(ex){
                var position= 'in catch';
                echo(pscope3, ex); //ReferenceError: i is not defined
                var ex = 'is catching';
                echo(pscope3, position);//in catch
                echo(pscope3, ex);//is catching
            }
            echo(pscope3, position);//in catch
            echo(pscope3, ex); //in capture 不是catch中赋的值
            echo(pscope3, window.ex); //undefined
        }
        capture();