PHP json format and js json format js cross-domain call implementation code_PHP tutorial

First look at a js function

In this function, the first alert(json[1].username); will prompt "candy". The json variable is an array object. So it needs to be called in the format of obj.username.
The second alert(json2[0][0]); will prompt “crystal”. The json2 variable is a complete json format. Both json and json2 variables achieve the same effect, but json2 is obviously much more streamlined than json.
This is JavaScript’s json format.
Let’s take a look at the json format in php.
Let’s look at a piece of code first


In this code, $arr is an array, we use json_encode to change $ arr is converted to json format.
This code will output:

[{"catid":"4","catname":"u7a0bu7a0b","meta_title":"u7a0bu7a0bu535au5ba2"},{"catid":"6" ,"catname":"climber","meta_title":"u6500u767bu8005"}]
This is how PHP handles json data.
For json data, PHP can also use the json_decode() function to convert json data into an array.
For example, in the above code, we use the json_decode function to process it. The above array will be printed out again.
$jsonstr = json_encode($arr);
$jsonstr = json_decode($jsonstr);
print_r($jsonstr);
Next, let’s take a look at php json data and js json data How to call each other.

We create a new php_json.php file

The code is as follows:

PS: At the end of the php_json.php file, var jsonstr=< ? = $jsonstr ? >; This sentence. This is to assign json format data to the jsonstr variable.
Let’s create another json.html file

The code is as follows:

In this way, when we view json.html, loadjson(jsonstr) will Tip "Chengcheng" and "climber"
This also realizes js cross-domain calling.