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JS using eval to parse JSON instances and considerations share _javascript Tips

Source: Internet
Author: User
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JSON (JavaScript Object notation) is a simple data format that is lighter than XML. JSON is the native format of JavaScript, which means that processing JSON data in JavaScript does not require any special APIs or toolkits.
The rule of JSON is simple: an object is an unordered set of ' name/value pairs '. An object begins with "{" (opening parenthesis), and "}" (closing parenthesis) ends. Each "name" followed by a ":" (colon); "' Name/value ' pairs" (comma) separated

Let's take a look at an analytic example

Copy Code code as follows:

<! DOCTYPE HTML PUBLIC "-//w3c//dtd XHTML 1.1//en" "Http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd" >
<meta http-equiv= "Content-type" content= "text/html; charset=gb2312 "/>
<title>eval function parsing JSON object </title>
<body>
<script type= "Text/javascript" >
var json=eval ({sitename: ' Dreamdu ', Sitedate:new Date (1980, 12, 17, 12, 0, 0)});
document.write (Json.sitename);
document.write ("<br/>");
document.write (json.sitedate);
</script>
</body>

Eval () issues to be noted in parsing JSON format strings
Issues to be aware of using eval () to parse JSON format strings
When you convert a JSON-formatted string to a JS object using the Eval function that is built into JavaScript, you need to wrap the string first with a pair of "()".
For example:
The Var strtest= "{id:" Cnlei ", url:" Http://www.jb51.net "}"; Convert to JS Object
Correct wording:
var objtest=eval ("(" +strtest+ ")");
Error wording:
var objtest=eval (strtest);

Complete test Code:

Copy Code code as follows:

<script type= "Text/javascript" >
<!--
var strtest= ' {id: ' cnlei ', url: ' http://www.jb51.net '} ';
var objtest=eval ("(" +strtest+ ")"); Correct wording
var objtest=eval (strtest); Wrong spelling
Alert (objtest.id+ "n" +objtest.url);
-->
</script>

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Related Keywords:
how to parse json parse array to json parse json to csv js json to array json to array js js string to json how to parse json response

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