JSON
- JavaScript Object Notation
- A Simple format designed to exchange data between different programming language
- Creating with JavaScript
var JSONstring =
{
"firstname": "Greg",
"email": "greg@fake_email.com",
"hobby":
[
{
"hobbyName": "sport",
"isHobby": "true"
},
{
"hobbyName": "reading",
"isHobby": "true"
},
{
"hobbyName": "music",
"isHobby": "false"
}
]
};
- Accessing with JavaScript
JSONstring.hobby[1].isHobby; // trueCreating JavaScript Objects
- JavaScript object <-> JSON string : http://www.json.org/json2.js
- Example
<html>
<head><TITLE>ditio.net jSon Tutorial</TITLE>
<script src="http://www.json.org/json2.js"></script>
<script>
// JavaScript source code will be here
function validate()
{
var p = document.forms['personal'];
var JSONObject = new Object;
JSONObject.firstname = p['firstname'].value;
JSONObject.email = p['email'].value;
JSONObject.hobby = new Array;
for(var i=0; i<3; i++)
{
JSONObject.hobby[i] = new Object;
JSONObject.hobby[i].hobbyName = p['hobby'][i].value;
JSONObject.hobby[i].isHobby = p['hobby'][i].checked;
}
JSONstring = JSON.stringify(JSONObject);
runAjax(JSONstring);
}
</head>
<body>
<form name="personal" action="" method="POST">
Name <input type="text" name="firstname"><br>
Email <input type="text" name="email"><br>
Hobby
<input type="checkbox" name="hobby" value="sport"> Sport
<input type="checkbox" name="hobby" value="reading"> Reading
<input type="checkbox" name="hobby" value="music"> Music
<input type="button" name="valid" value="Validate" onclick="validate()">
</form>
</body>
</html>
Sending JSON object to PHP with AJAX - Example
var request;
function runAjax(JSONstring)
{
// function returns "AJAX" object, depending on web browser
// this is not native JS function!
request = getHTTPObject();
request.onreadystatechange = sendData;
request.open("GET", "parser.php?json="+JSONstring, true);
request.send(null);
}
// function is executed when var request state changes
function sendData()
{
// if request object received response
if(request.readyState == 4)
{
// parser.php response
var JSONtext = request.responseText;
// convert received string to JavaScript object
var JSONobject = JSON.parse(JSONtext);
// notice how variables are used
var msg = "Number of errors: "+JSONobject.errorsNum+
"
- "+JSONobject.error[0]+
"
- "+JSONobject.error[1];
alert(msg);
}
}
