Question on Javascript Function Parameters

Question

I was trying to write some javascript function and realised that

function testFunction(input_1, input_2, input_3) {
       alert("alert");
}

however when i call the function like this:

<input type="button" value="click" onclick="testFunction("1", "2")">

why will it still work even with just two parameters?

question from:https://stackoverflow.com/questions/6446304/question-on-javascript-function-parameters

Answer 1

You can call a Javascript function with any number of parameters, regardless of the function's definition.

Any named parameters that weren't passed will be undefined.

Extra parameters can be accessed through the arguments array-like object.