Using jQuery to store the state of a complicated form

Question

I have a rather complicated form with many "steps" in it that are filled in by the user. Some steps (think of them as form segments) have default options, but on clicking a "enter custom values," they display a hereto hidden set of fields that the user can enter info in. Here is an example

<div id="#s1_normal">
<input type="radio" name="mode" value="a"> Mode A
<input type="radio" name="mode" value="b"> Mode B
Choose one of the above for applying average coefficient 
values of "a" or "b" to 100% of your product or
<a href="#" onclick="toggleCustom('s1');">enter custom values</a>
</div>

<div id="#s1_custom">
%a: <input type="text" name="perc_a"> coeff. a <input type="text" name="coeff_a">
%b: <input type="text" name="perc_b"> coeff. b <input type="text" name="coeff_b">
Enter custom values above or 
<a href="#" onclick="toggleCustom('s1');">choose average values</a>

There are several such segments, for example, #s1 .. #s7. Here is my task. I want to enable the user to save the state of a form. So, once a user has filled out the entire form, choosing average defaults for some segments, and entering custom values for other, the user is able to click a button and have the entire state saved for thawing later. I am thinking, if I can save the state in an object that I can serialize, I can save it in a db table or some other persistent storage.

The user can come back at a later time and re-construct the entire previous session.

How do I do this? There is the getAttributes plugin http://plugins.jquery.com/project/getAttributes, and there is the jQuery serialize method, but I can't for the life of me get started. Please nudge me in the right direction.

Answer 1

Here are a couple functions to help with this process. formToString serializes a form as a string, and stringToForm does the reverse:

function formToString(filledForm) {
    formObject = new Object
    filledForm.find("input, select, textarea").each(function() {
        if (this.id) {
            elem = $(this);
            if (elem.attr("type") == 'checkbox' || elem.attr("type") == 'radio') {
                formObject[this.id] = elem.attr("checked");
            } else {
                formObject[this.id] = elem.val();
            }
        }
    });
    formString = JSON.stringify(formObject);
    return formString;
}
function stringToForm(formString, unfilledForm) {
    formObject = JSON.parse(formString);
    unfilledForm.find("input, select, textarea").each(function() {
        if (this.id) {
            id = this.id;
            elem = $(this); 
            if (elem.attr("type") == "checkbox" || elem.attr("type") == "radio" ) {
                elem.attr("checked", formObject[id]);
            } else {
                elem.val(formObject[id]);
            }
        }
    });
}

Usage:

// Convert form to string
var formString = formToString($("#myForm"));
// Save string somewhere, e.g. localStorage
// ...

// Restore form from string
stringToForm(formString, $("#myForm"));

Answer 2

I would start by using the dumbFormState jQuery plugin.

That plugin actually automatically saves things while you are typing etc. so when they come back, its already filled out again and you don't need server-side to do it.

After that, I would create further jQuery to load after the dumbFormState plugin to then show/hide the areas that are filled out. Its no problem if you call this before someone ever filled out their form because it will be blank and your logic should not show/hide things that are blank anyway.