函数变量和函数变量具有相同的名称。 如何进入？

Question

I was wondering how does javascript(if possible) access a variable that has the same name as the variable input of the function.

function myfunc(var1)
{
    var var1 = "World";
    alert(var1);
}

How can I tell the function which var1 to print?

Answer 1

That doesn't actually define a second variable with the same name. Even with the var statement you are just overwriting the function parameter of the same name.

Just give your second variable a unique name.

(By the way, even if this actually worked it would still be a bad idea because it would make your code hard to read.)

Answer 2

nnnnnn is correct, I tested it. Arguments that are passed to a function can be accessed in 2 ways, by their parameter name and through the arguments variable. arguments[0] would be the value of the first parameter.

In the example below you would expect 2 alerts, the first one saying "Hello" and the second saying "World" . But they both say "World" proving that assigning var1 actually changes the value of the argument being passed to the function.

function myfunc(var1) {
    var var1 = "World";
    alert(arguments[0]);
    alert(var1);
}

myfunc("Hello");