1⟩ How to convert JSON Text to a JavaScript Object?
One of the most common use of JSON is to fetch JSON data from a web server (as a file or as an HttpRequest), convert the JSON data to a JavaScript object, and then it uses the data in a web page.
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One of the most common use of JSON is to fetch JSON data from a web server (as a file or as an HttpRequest), convert the JSON data to a JavaScript object, and then it uses the data in a web page.
JSON stands for JavaScript Object Notation, JSON is lightweight text-data interchange format it is language independent mean JSON uses JavaScript syntax for describing data objects, but JSON is still language and platform independent. JSON parsers and JSON libraries exists for many different programming languages. It is "self-describing" and easy to understand.
The eval() function can compile and execute any JavaScript. This represents a potential security problem.
It is safer to use a JSON parser to convert a JSON text to a JavaScript object. A JSON parser will recognize only JSON text and will not compile scripts.
Native JSON support is included in newer browsers and in the newest ECMAScript (JavaScript) standard.
Web Browsers Support:
► Firefox (Mozilla) 3.5
► Internet Explorer 8
► Chrome
► Opera 10
► Safari 4
JSON is smaller than XML, and faster and easier to parse. Below is a basic syntax of JSON
JSON CODE
{
"studeents": [
{ "firstName":"Ali" , "lastName":"Khan" },
{ "firstName":"John" , "lastName":"Sena" },
{ "firstName":"Kate" , "lastName":"Winslet" }
]
}
JSON syntax is a subset of the JavaScript object notation syntax.
► Data is in name/value pairs
► Data is separated by comma
► Curly brackets holds objects
► Square brackets holds arrays
JSON values can be:
► A number (integer or floating point)
► A string (in double quotes)
► A Boolean (true or false)
► An array (in square brackets)
► An object (in curly brackets)
► null
JSON arrays are written inside square brackets.
An array can contain multiple objects:
JSON Arrays
{
"studeents": [
{ "firstName":"Ali" , "lastName":"Khan" },
{ "firstName":"John" , "lastName":"Sena" },
{ "firstName":"Kate" , "lastName":"Winslet" }
]
}
Because JSON uses JavaScript syntax, no extra software is needed to work with JSON within JavaScript.
With JavaScript you can create an array of objects and assign data to it like this:
JSON CODE
{
"studeents": [
{ "firstName":"Ali" , "lastName":"Khan" },
{ "firstName":"John" , "lastName":"Sena" },
{ "firstName":"Kate" , "lastName":"Winslet" }
]
}
The file type for JSON files is ".json"
JSON objects are written inside curly brackets,
Objects can contain multiple name/values pairs.
The MIME type for JSON text is "application/json"