Create/ creating the variable's dict dynamically and print

Question

I want print the dict a in alert , (it is possible?) or print in the third's textarea (three) with id=p. I read on this question and I used

document.getElementById("p").value=JSON.stringify(a);;
    alert("myObject is " + a.toSource());
    console.log(a);

These not function. The example is :

<!DOCTYPE HTML>
<html>
<head>
<title>Example - print the dict</title>
</head>
<body>

<input id = 'button1' type = 'button' value = 'print the dict' onclick="updateHistory()"/>

<script type = 'text/javascript'>

var count ="?foo=1&oo=298529982";

function updateHistory()
{

 var a = new Array();

for (var i = 0; i < document.formparam.elements.length; i++)
{

    var field = document.formparam.elements[i];
    a[field.name] = field.value;
}

document.getElementById("p").value=JSON.stringify(a);;
alert("myObject is " + a.toSource());
console.log(a);
}


</script>
<form method="GET" name="formparam" id="formparam" ><table><tr><td><textarea name="name" >john</textarea></td><td><textarea name="surname">jackold</textarea></td></tr></table></form>
<textarea id="p"></textarea>
</body>
</html>

Are you meaning you want to change `console.log(a)` to `alert(a)`? If so, you should just start using a console instead. — Paul, Apr 16 '13 at 01:41
no I want print the dict in one alert or in textarea, I used the Firebug and I see this dict but I'm not sure — Mirko Cianfarani, Apr 16 '13 at 01:45
`.toSource()` is not a standard function, but do you see the expected value inside the text area? — Ja͢ck, Apr 16 '13 at 01:50
@MirkoCianfarani That's because the base type of `a` is an array and you're not adding items using `.push()`. — Ja͢ck, Apr 16 '13 at 01:52
@MirkoCianfarani, the way you are using the array [] in your code will no work. You need an object {}. — plalx, Apr 16 '13 at 01:53
There are no dictionaries in javascript, as far as I am aware. There are objects, and arrays. — Daedalus, Apr 16 '13 at 01:53

score 3 · Accepted Answer · answered Apr 16 '13 at 01:57

Using JSON.stringify() on an array will iterate over the array like so:

for (var i = 0; i < a.length; ++i) {
    // process value of a[i]
}

But because you're adding properties to the object using a[field.name], those are not added to the list of array items, unlike a.push(value). As such, JSON.stringify() will print [].

You should either:

Define a as an object, i.e. var a = {};

Iterate over the keys yourself:

for (var k in a) {
    if (a.hasOwnProperty(k)) {
        // process value of a[k]
    }
}

plalx · Answer 2 · 2013-04-16T01:58:22.407

2

var a = new Array();

should be

var a = {}; or var a = new Object();

There are no dictonnaries in JavaScript, however, you can use an object as a key/value store. To alert the object as JSON, you can just do alert(JSON.stringify(a));.

edited Apr 16 '13 at 01:58

answered Apr 16 '13 at 01:48

plalx

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Create/ creating the variable's dict dynamically and print

2 Answers2