How to pass a form input value into a JavaScript function

Question

I have a generic JavaScript function which takes one parameter

function foo(val) { ...} 

and I want to call the function when submit a form

Answer 1

Give your inputs names it will make it easier

UPDATE:

If you give your button an id things can be even easier:

Javascript:

var button = document.getElementById("theButton"),
value =  button.form.valueId.value;
button.onclick = function() {
    foo(value);
}