//方式1，調用函數，得到返回值。強制運算符使函數調用執行
(function(x,y){
alert(x+y);
return x+y;
}(3,4));

(function(x,y){
alert(x+y);
return x+y;
})(3,4);

//方式三，調用函數，忽略返回值
void function(x) {
x = x-1;
alert(x);
}(9);

void function(x) {
x = x-1;
alert(x);
}(9);

function(x,y){
alert(x+y);
return x+y;
}(3,4);