JS Gets the example of the length of the JSON object data

The simplest way to get the JSON data length method jsonlist.length

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var str = ' [{"username": "Liu Xiaofei", "Bay": "2010/06/17"},{"username": "From Small P", "Bay": "2010/06/11"}] ';

Alert (str.length) In fact, it outputs a result length of 2

Here's what I do with JavaScript code, why do I only provide JavaScript code? Since other languages have more or less provided some information about JSON, but JavaScript does not provide much, and then in the process of web development, now relies more on jquery, so don't say much, see code:

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function Getjsonobjlength (jsonobj) { var Length = 0; For (var item in jsonobj) { length++; } return Length; }

The use method is also simple, we assume that there is a JSON object is "Jsontemp", the specific content is {["name": "John", "Age": 18],["name": "Dick", "age": 19]}. The only things we need to do when using JavaScript are the following:

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var count = getjsonobjlength (jsontemp);

To develop applications, such as the need to read each object in JSON in a traversal manner, follow these steps:

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For (I=0;i<getjsonobjlength (jsontemp); i++) { name = Jsontemp[i].name; age = Jsontemp[i].age; }

Okay, here's the basic application.

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Discussion on the method of reading JSON in S

JS Way to read JSON I have two kinds of contacts:
Method One: Function construction definition method returns

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var Strjson = "{name: ' JSON name '}";//Get JSON var obj = new Function ("return" + Strjson) ()//converted JSON object alert (obj.name);//json name

Method Two: The famous eval function in JS

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var Strjson = "{name: ' JSON name '}";//Get JSON var obj = eval ("(+ Strjson +)");//Converted JSON object alert (obj.name);//json name

The second way to be aware of this is that the object expression {' name ': ' JSON name '} must be extended with ' () ' otherwise

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var Strjson = "{name: ' JSON name '}"; var obj = eval (Strjson); alert (obj.constructor);//string constructor alert (obj.name);//undefine

An object expression must be extended to eval execution to generate an anonymous object!