Develop Reference

Passing an object by it's name through HTML to javascript

It's a pretty simple question and I'm going insane over here googling this all around and getting all these insanely non related answers.
here is the code:
function Banana(boja, duzina) {
this.boja = boja;
this.duzina = duzina;
}
var zut = new Banana("zuta", 12);
function fja(obj) {
var rez = "";
for (var key in obj)
var rez += key + " = "
obj.key + "<br/>";
document.getElementById('div1').innerHTML = rez;
}
<button onclick="fja();">klikni</button>
<div id='div1'>xd</div>
Is it possible to pass an instance of an object "zut" to this function through HTML? If yes,how,if not,how am I supposed to do it through JS?
I want div1 html to be turned into:
boja = zuta
duzina = 12
thanks for answers

function Banana(boja, duzina) {
this.boja = boja;
this.duzina = duzina;
}
var zut = new Banana("zuta", 12);
function fja(obj) {
var rez = "";
for (var key in obj)
rez += key + " = "+ obj[key] + "<br/>";
document.getElementById('div1').innerHTML = rez;
}
<button onclick="fja(zut);">klikni</button>
<div id='div1'>xd</div>

You certainly can, although why your code doesn't work is because
1) - You're re declaring the variable rezand assigning to it using += which is no valid.
2) - obj.key is not valid, because there no such property called key, To access it you need to use brackets obj[key] nowkey will be considered as a variable and it's value will be used to get the property's value.
3) - You missed a + in this line var rez += key + " = " (HERE) obj.key + "<br/>";
4) - Your call to the method in the html is missing the argument.
you can either use onclick="fja(new Banana('zuta', 12));
Or declare the object inline in the HTML, or declare it in the js and pass it name
//in the Js
var zut = new Banana("zuta", 12);
//in the HTML
onclick="fja(zut);
Example one
function Banana(boja, duzina) {
this.boja = boja;
this.duzina = duzina;
}
function fja(obj) {
var rez = "";
for (var key in obj)
rez += key + " = " + obj[key] + "<br/>";
document.getElementById('div1').innerHTML = rez;
}
<button onclick="fja(new Banana('zuta', 12));">klikni</button>
<div id='div1'>xd</div>
Example Two
function Banana(boja, duzina) {
this.boja = boja;
this.duzina = duzina;
}
var zut = new Banana("zuta", 12);
function fja(obj) {
var rez = "";
for (var key in obj)
rez += key + " = " + obj[key] + "<br/>";
document.getElementById('div1').innerHTML = rez;
}
<button onclick="fja(zut);">klikni</button>
<div id='div1'>xd</div>

Function Scope issue when declaring an array of objects

This is the code that I currently have, one problem that is happening is I cannot use test() because presets[index].name and value are not visible outside of their function scope, how should I declare my array of objects in the global scope in order for me to be able to access these two variables in other functions?
var presets = [];
var index;
function CreatePresetArray(AMib, AVar) {
var parentpresetStringOID = snmp.getOID(AMib, AVar);
var presetStringOID = parentpresetStringOID;
parentpresetStringOID = parentpresetStringOID.substring(0, parentpresetStringOID.length - 2);
log.error("parentpresetStringOID is " + parentpresetStringOID);
var presetswitches = {};
for (var i = 1; i < 41; i++) {
presets.push(presetswitches);
try {
log.error("presetStringOID before getNextVB= " + presetStringOID);
vb = snmp.getNextVB(presetStringOID);
presetStringOID = vb.oid;
log.error("presetStringOID after getnextVB= " + presetStringOID);
var presetStringVal = snmp.get(presetStringOID);
log.error("presetStringVal= " + presetStringVal);
index = i - 1;
presets[index].name = presetStringOID;
presets[index].value = presetStringVal;
log.error("preset array's OID at position [" + index + "] is" + presets[index].name + " and the value stored is " + presets[index].value);
//log.error("presets Array value ["+index+"] = "+presets[index].configs);
if (presetStringOID.indexOf(parentpresetStringOID) != 0) {
break;
}
} catch (ie) {
log.error("couldn't load preset array " + index);
};
};
}
CreatePresetArray(presetMib, "presetString");
function test() {
for (i = 1; i < 41; i++) {
log.error("test" + presets[index].name + " " + presets[index].value);
};
}
test();

The for loop in your function test iterates over i but uses index inside the loop. Perhaps you meant to use
for (i = 0; i < 40; i++) { // 1 lower as you were using `index = i - 1` before
log.error("test" + presets[i].name + " " + presets[i].value);
}
Re-wrote your code. I don't think I made that much by way of change. If this doesn't clear up your problem, consider: Is the catch happening each iteration? Is the problem actually coming from a different method which is only visible here? Also, consider logging the whole presets Array when debugging to see what it looks like.
var presets = [];
function CreatePresetArray(AMib, AVar) {
var parentPresetOID, presetOID, presetValue, preset, vb, i;
parentPresetOID = snmp.getOID(AMib, AVar);
presetOID = parentPresetOID; // initial
parentPresetOID = parentPresetOID.substring(0, parentPresetOID.length - 2);
log.error("parentPresetOID is " + parentPresetOID);
presets = []; // empty array in case not already empty
for (i = 0; i < 40; ++i) {
try {
preset = {}; // new object
// new presetOID
vb = snmp.getNextVB(presetOID);
presetOID = vb.oid;
log.error("presetOID after getnextVB= " + presetOID);
// new value
presetValue = snmp.get(presetOID);
log.error("presetValue= " + presetValue);
// append data to object
preset.name = presetOID;
preset.value = presetValue;
// append object to array
presets.push(preset);
// more logging
log.error(
"preset array's OID at position [" + i + "]" +
" is" + presets[i].name + " and " +
"the value stored is " + presets[i].value
);
if (presetOID.indexOf(parentPresetOID) !== 0) {
break;
}
} catch (ie) {
log.error("couldn't load preset array " + i);
if (presets.length !== i + 1) { // enter dummy for failed item
presets.push(null);
}
}
}
}

Two options come to mind immediately:
you could pass the preset array as a argument to test().
You could put both CreatePresetArray() and test() inside a wrapper function and declare preset array at the top of your wrapper. That would give them both access to the variable.
It's generally considered Bad Form to declare globals if it can be avoided. Pollutes the namespace.

Javascript reflection - generic toString

now when I put my own Object in alert function I see
[Object object]
that is pointless information. is there any way using reflection to get all fields and values of those fields?

JSON.stringify is often times builtin and can serialize most objects you pass to it.
That said, you should probably just use a debugger or console.log instead of alert-ing things.

Here is one of many. But better to use console.log() then alert
function objectToString(o){
var parse = function(_o){
var a = [], t;
for(var p in _o){
if(_o.hasOwnProperty(p)){
t = _o[p];
if(t && typeof t == "object"){
a[a.length]= p + ":{ " + arguments.callee(t).join(", ") + "}";
}
else {
if(typeof t == "string"){
a[a.length] = [ p+ ": \"" + t.toString() + "\"" ];
}
else{
a[a.length] = [ p+ ": " + t.toString()];
}
}
}
}
return a;
}
return "{" + parse(o).join(", ") + "}";
}

sure, maybe something like
function alertObject(0){
var str = "";
for(i in o)
str += i + " " + o[i] + "\n";
alert(str);
}
Edit :: Note this is just a silly little example.

convert JSON object to XML using javascript

I want to convert a JSON object to a XML String and I can't figure a proper way to do it.
I've found a neat little jQuery plugin called json2xml at https://gist.github.com/c4milo/3738875 but it doesn't escape the data.
How can I escape the data properly so that the browser's XML parser will work?

You can try this small library http://code.google.com/p/x2js/

There is no unique way of doing this. You should be using XML with a schema only, and JSON doesn't have such a schema. Any such transformation when done naively is likely to break.
Why don't you just use XML or JSON consequently?

You can use the external js available by google named x2js.js
You can see the demo over here.
jsFiddle Demo

you can use this function in your code to convert JSON to XML in js
var json2xml = function (o) {
var tab = "\t";
var toXml = function (v, name, ind) {
var xml = "";
if (v instanceof Array) {
for (var i = 0, n = v.length; i < n; i++)
xml += ind + toXml(v[i], name, ind + "\t") + "\n";
}
else if (typeof (v) == "object") {
var hasChild = false;
xml += ind + "<" + name;
for (var m in v) {
if (m.charAt(0) == "#")
xml += " " + m.substr(1) + "=\"" + v[m].toString() + "\"";
else
hasChild = true;
}
xml += hasChild ? ">" : "/>";
if (hasChild) {
for (var m in v) {
if (m == "#text")
xml += v[m];
else if (m == "#cdata")
xml += "<![CDATA[" + v[m] + "]]>";
else if (m.charAt(0) != "#")
xml += toXml(v[m], m, ind + "\t");
}
xml += (xml.charAt(xml.length - 1) == "\n" ? ind : "") + "</" + name + ">";
}
}
else {
xml += ind + "<" + name + ">" + v.toString() + "</" + name + ">";
}
}
return xml;
};
you get XML DOM in return, which in return you need to serialize
so in the main
var xmlDOM = json2xml(eval(jsonObj));
var oSerializer = new XMLSerializer();
var sXML = oSerializer.serializeToString(xmlDOM);

How can I know all the attributes a javascript object has?

Is there something like Java's reflection where I can know what attributes are available?

for(var key in myObject) {
//do something with key
}
that enumerates through all properties
all properties for the window object http://jsfiddle.net/KdyLG/

This is one function that I use. You can specify which level of the array you which to dump.
alert(dump(myArray));
function dump(arr,level) {
var dumped_text = "";
if(!level) level = 0;
//The padding given at the beginning of the line.
var level_padding = "";
for(var j=0;j<level+1;j++) level_padding += " ";
if(typeof(arr) == 'object') { //Array/Hashes/Objects
for(var item in arr) {
var value = arr[item];
if(typeof(value) == 'object') { //If it is an array,
dumped_text += level_padding + "'" + item + "' ...\n";
dumped_text += dump(value,level+1);
} else {
dumped_text += level_padding + "'" + item + "' => \"" + value + "\"\n";
}
}
} else { //Stings/Chars/Numbers etc.
dumped_text = "===>"+arr+"<===("+typeof(arr)+")";
}
return dumped_text;
}

A way to do it:
for(var attrib in myObject){
if(typeof attrib != 'function') {
alert('this is attribute ' + attrib + 'with value' + myObject[attrib]);
} }