How to turn a html form into a complex JavaScript object

Question

Is there a way to turn a form into a complex JavaScript object based some structured form?

Now, I have no idea if this should be done in a better way, but basically I want something like this:

<form>
   <input name="Foo" value="1" />
   <input name="Parent.Child1" value="1" />
   <input name="Parent.Child2" value="2" />
</form>

and I want this in JavaScript:

var form = GetForm();
var obj = ConvertFormToComplexObject(form);

//
// Followings should be true
// 
// obj.Foo == 1;
// obj.Parent != null
// obj.Parent.Child1 == 1;
// obj.Parent.Child2 == 2;
//

Any suggestions?

Thanks,

To what end? This just seems like a variation on basic DOM scripting; why not just learn to use normal DOM scripting? — Richard JP Le Guen
– Richard JP Le Guen, Commented Aug 5, 2010 at 19:56
Hm.. basically, I have a form with dynamic form elements. The user can add a list of "objects" where each "object" each contains an integer and a string. I can keep the form flat by having a naming convention like name="1_Integer", or name="2_String", but I will have to write a parser. If I build the JavaScript object correctly. I can use Json to serialize it and let Json take care of the complexity. — Chi Chan
– Chi Chan, Commented Aug 5, 2010 at 20:41

Chi Chan · Accepted Answer · 2010-08-06 20:47:26Z

I wrote a plugin to do just that. Hope it will help someone out there. Let me know if you find any bugs.

Here's the code for serializeObject.js:

$.fn.serializeObject = function() {
    var o = {};
    var a = this.serializeArray();
    $.each(a, function() {

        var arrayIndex = function(name) {
            //note: 2d array not handled

            var startIndex = name.indexOf('[');
            var endIndex = name.indexOf(']');

            if (startIndex == -1 || endIndex == -1 || endIndex != name.length - 1)
                return null;

            return name.substr(startIndex + 1, endIndex - startIndex - 1);
        }

        var trimArrayIndex = function(name) {
            var startIndex = name.indexOf('[');
            return name.substr(0, startIndex);
        }

        var createObject = function(obj, className, value) {
            if (className.length == 0)
                return;

            var classNames = className.split(".");

            if (classNames.length == 1) {

                if (obj[classNames[0]] == null) {
                    obj[classNames[0]] = value;
                }
                else if (obj[classNames[0]] instanceof Array) {
                    obj[classNames[0]].push(value);
                }
                else {
                    var temp = obj[classNames[0]];

                    obj[classNames[0]] = new Array();
                    obj[classNames[0]].push(temp);
                    obj[classNames[0]].push(value);
                }

                return;
            }

            var index = arrayIndex(classNames[0]);
            var isArray = index != null;

            if (!isArray) {
                if (obj[classNames[0]] == null) {
                    obj[classNames[0]] = new Object();
                }

                createObject(obj[classNames[0]], className.substr(classNames[0].length + 1), value);
            }
            else {
                var aryName = trimArrayIndex(classNames[0]);

                if (obj[aryName] == null) {
                    obj[aryName] = new Array();
                }
                else if (!obj[aryName] instanceof Array) {
                    throw "unable to serialize " + aryName + " as an array";
                }

                var ary = obj[aryName];
                var nextObj;

                if (ary[parseInt(index)] == null) {
                    ary[parseInt(index)] = new Object();
                }

                nextObj = ary[parseInt(index)];

                createObject(nextObj, className.substr(classNames[0].length + 1), value);
            }
        }

        createObject(o, this.name, this.value || '');
    });
    return o;
};

$.fn.replaceStarWithIndex = function() {
    var a = this.serializeArray();
    var form = this;


    var arrayIndex = function(name) {
        var startIndex = name.indexOf('[');
        var endIndex = name.indexOf(']');

        if (startIndex == -1 || endIndex == -1) {
            return null;
        }

        return name.substr(startIndex + 1, endIndex - startIndex - 1);
    }

    var trimArrayIndex = function(name) {
        var startIndex = name.indexOf('[');
        return name.substr(0, startIndex);
    }

    for (var key in a) {
        var index = arrayIndex(a[key].name);

        if (index == null || index != "*") {
            continue;
        }

        var count = 0;
        var trimName = trimArrayIndex(a[key].name);

        while (true) {
            var elementName = a[key].name.replace('*', count);
            var element = form[0][elementName];

            if (element == null) {
                $(form[0][a[key].name]).first().attr('name', elementName);
                break;
            }
            count++;
        }
    }
}

Here's the test:

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
<head>
    <title>Test</title>
    <link rel="stylesheet" href="http://github.com/jquery/qunit/raw/master/qunit/qunit.css" type="text/css" media="screen" />

    <script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.4.2/jquery.min.js" ></script>
    <script type="text/javascript" src="http://github.com/jquery/qunit/raw/master/qunit/qunit.js" ></script>
    <script type="text/javascript" src="serializeObject.js" ></script>
</head>

<body>

<h1 id="qunit-header">Test serializeObject</h1>
<h2 id="qunit-banner"></h2>
<h2 id="qunit-userAgent"></h2>
<ol id="qunit-tests"></ol>

<!--Test Form -->

<form id="form1" style="display:none;">
    <input type="text" name="Parent.Child1" value="child1"/>

    <input type="text" name="Parent.Child2" value="child2a"/>
    <input type="text" name="Parent.Child2" value="child2b"/>

    <input type="text" name="Parent.Child3" value="3"/>
    <input type="text" name="Parent.Child3" value="2"/>
    <input type="text" name="Parent.Child3" value="1"/>

    <input type="text" name="Parent.Child4[0].Child1" value="11" />
    <input type="text" name="Parent.Child4[0].Child2" value="aa" />

    <input type="text" name="Parent.Child4[1].Child1" value="22" />
    <input type="text" name="Parent.Child4[1].Child2" value="bb" />



</form>   

<form id="form2" style="display:none;">
    <input type="text" name="Child1[0].Child1" value="0" />
    <input type="text" name="Child1[*].Child1" value="1" />
    <input type="text" name="Child1[*].Child1" value="2" />

    <input type="text" name="Child2[2]" value="2" />
    <input type="text" name="Child2[*]" value="0" />
    <input type="text" name="Child2[*]" value="1" />
</form> 

<script type="text/javascript">
    $(document).ready(function() {
        var obj = $('#form1').serializeObject();

        test("Parent should exist", function() {
            equals(true, obj.Parent != null);
        });

        test("Child1 should exist within parent", function() {
            equals(true, obj.Parent.Child1 != null);
        });

        test("Should create array for items with same name", function() {
            equals("child2a", obj.Parent.Child2[0]);
            equals("child2b", obj.Parent.Child2[1]);
            equals("3", obj.Parent.Child3[0]);
            equals("2", obj.Parent.Child3[1]);
            equals("1", obj.Parent.Child3[2]);
        });


        test("Should allow array of objects", function() {
            equals("11", obj.Parent.Child4[0].Child1);
            equals("aa", obj.Parent.Child4[0].Child2);
            equals("22", obj.Parent.Child4[1].Child1);
            equals("bb", obj.Parent.Child4[1].Child2);
        });

        $('#form2').replaceStarWithIndex();

        test("Should replace * with index", function() {
            equals("0", $('#form2 input[name="Child1[0].Child1"]').val());
            equals("1", $('#form2 input[name="Child1[1].Child1"]').val());
            equals("2", $('#form2 input[name="Child1[2].Child1"]').val());

            equals("0", $('#form2 input[name="Child2[0]"]').val());
            equals("1", $('#form2 input[name="Child2[1]"]').val());
            equals("2", $('#form2 input[name="Child2[2]"]').val());
        });

    });
</script>

</body>
</html>

KoolKabin · Accepted Answer · 2010-08-05 19:57:15Z

0

i guess you are asking for document.forms[0]

something like:

var form = document.forms[0]; //or can be document.getElementByName...

then you can access its values as you are trying: form.Foo = 1

you do not need to convert it to complex object DOM itself is sufficent for that

answered Aug 5, 2010 at 19:57

KoolKabin

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Comments

Koerr · Accepted Answer · 2010-08-05 20:19:25Z

0

var form = document.forms[0];

return a HTML Element Object,you can use

form.Foo

get a HTML Element too

but if you want to get value,must use:

form.Foo.value

or

form['Parent.Child1'].value;

you can see this DEMO

P.S. i think ConvertFormToComplexObject() method is not good.you don't need to create it.

answered Aug 5, 2010 at 20:19

Koerr

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1 Comment

Chi Chan Over a year ago

Thanks Zenofo, but I want "Parent" to be an object so I can have the option to serialize it into Json if I wanted to. In your case, form.Parent is null or form.Parent.Child1 gives an error

Andreas Köberle · Accepted Answer · 2010-08-05 20:51:50Z

0

Its a names[0]very basic version but it should give you a basic understanding on how this work.

$(function(){
    var elements = document.forms[0].elements,
        foo = {};
    for(var i=0; i<elements.length; i++) {
        var element = elements[i];
        var names = element.name.split('.');
        if(names.length >1) {
            foo[names[0]] = foo[names[0]] || {};
            foo[names[0]][names[1]] = element.value;
        } else {
         foo[names[0]] = element.value;
        }

    }
    console.log(foo)
});

answered Aug 5, 2010 at 20:51

Andreas Köberle

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Comments

Daniel Beardsley · Accepted Answer · 2010-08-05 21:30:23Z

0

Numerous Javascript libraries have this functionality. I suggest you use their implementation, or at least see how they've done it.

Prototype: http://www.prototypejs.org/api/form/serialize

Usage: $('id-of-form').serialize(true)

answered Aug 5, 2010 at 21:30

Daniel Beardsley

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1 Comment

Chi Chan Over a year ago

I have looked at the jQuery one, but it doesn't do the "structured" object serialization. In fact, this it doesn't even serialize it into an object. The closest I got it this: stackoverflow.com/questions/1184624/…

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