Quick methods Javascript/Jquery/etc to retrieve all aspnet:textbox (input) contained in a form, excluding other elements

I created a 'test Label' or alert to see values of variables (some way to know values of variables like in Matlab?)

How can I change so i can retrieve the correct number of elements as required (and not value '0' or 'all elements' or 'errors')?

Code is this:

var lenform = document.getElementById("ActionInMoveID").length;
var selform = document.getElementById("ActionInMoveID");

var count = 0;
for (var k = 0; k < lenform; k++) 
    {
    if (selform.elements[k].tagName == "input")
    count++;
    }
alert(count);

Thanks a lot