获取函数内里面的数据，总结

var str = '';
function fn1(){
var a = '大鸡腿~';
str = a;
}
fn1();
// alert( str );

function fn2(){
var a = '9999999克拉钻石23456789';
fn3(a);
}
fn2();

function fn3(a){
alert(a);
}