JQuery loop through input elements inside javascript function

You are missing a . and probably a .find before .each. Below code is what it should look like:

$(document).find("input[class=domain]").each(function() {
      //TO DO: Refresh jsonObj 
      alert(domain); 
}); 

UPDATE

With respect to your second question I would have shortened the code as below if the lines inside your .each was same as it would be in refreshData function:

jsonObj = [];
$(document).ready(function(){
    refreshData();//call once on DOM Load
    $('.domain').change(refreshData); //attach it as named function to change event
});

function refreshData() {
    //keep all this code here
    $(".domain").each(function() {
        var domain = $(this).attr("name");
        var score = $(this).val();

        item = {}
        item["domain"] = domain;
        item["score"] = score;

        jsonObj.push(item);
    });        
}

I have done some rectification and you can shorten it like:

<script>        
    jsonObj = []; // array declaration
    $(document).ready(function(){
        $("input.domain").change(function(){ // <----better to use a class selector
            refreshData($("input.domain")); // <----pass the object in the function                                                         
        }).change(); //<----trigger it on load to execute       
    });

    function refreshData(el) { // get the passed object in the func arg
        $(el).each(function() { // <----have a loop on it this way
            var domain = $(this).attr("name"); // extract the name on current object in collection
            var score = this.value; // get the value of the current object in iteration
            var item = {}; // declare a new object
                item["domain"] = domain; // set new prop and assign value here
                item["score"] = score; // set new prop and assign value here
            jsonObj.push(item); // now push the object in the array.
        });         
    }
</script> 

This expression is wrong for some reasons:

$(document)("input [class=domain]")

A. There must be no space between input and [class=domain]. This is the difference between "input that has the class domain" (input[class=domain]) and "input that one of its sub-nodes has the class domain" (input [class=domain]).

B. In order to query inside a jQuery element you need to use the find method like this: $(document).find("input [class=domain]"). But because document is the root element, you can just write $("input [class=domain]").

P.S

In CSS-selectors (like jQuery) there is a special syntax for searching classes, so instead you can just write input.domain.

So this how the line should look at last: $("input.domain").each...

You can read more about css selectors here.

Strange code...

$(document)("input [class=domain]").each

Try this:

$("input[class=domain]").each