html jump parameters

HTML jump parameters: Tips for passing parameters using GET and POST methods

HTML is a commonly used front-end programming language. In practical applications, sometimes it is necessary to pass some parameters while jumping on the page. For example, if you search for keywords in the search page, then jump to the search results page, and display relevant search results in the results page, you need to pass parameters. This article will introduce how to jump parameters in HTML, and how to pass parameters using GET and POST methods.

1. How to jump parameters in HTML

To jump parameters in HTML pages, there are two methods: URL parameters to jump and form submission to jump.

1. URL parameter jump

URL parameter jump refers to appending parameters directly to the end of the URL address, so that when jumping to the target page, the background can obtain the parameters through URL parsing .

The URL address format is as follows:

http://www.example.com/index.php?key=value

where key is the parameter name and value is the parameter value. If you need to pass multiple parameters, you can use & symbols to connect. For example:

http://www.example.com/index.php?key1=value1&key2=value2

In the hyperlink tag <a></a> that needs to be jumped, the value of the href attribute is the URL address of the jump destination, for example:

<a href="http://www.example.com/index.php?key=value">跳转到目的地</a>

When the user clicks this link, it will automatically jump to the target page and bring the parameters.

2. Form submission to achieve jump

Form submission to achieve jump means passing the parameters to the background through form submission, and the background obtains the parameters by parsing the form data.

Common forms of HTML forms include text input boxes, drop-down selection boxes, radio buttons, check boxes, etc. To submit a form, a handler for the form data must be defined in the

tag.

For example:

<form method="post" action="http://www.example.com/index.php">
    <input type="text" name="key1" value="value1">
    <input type="text" name="key2" value="value2">
    <input type="submit" name="submit" value="提交">
</form>

In the above code, method="post" means using the POST method to submit the form, action="http://www. example.com/index.php" means to submit the form to the specified page.

Among them, the name attribute in the <input> tag represents the parameter name, and the value attribute represents the parameter value. When the form is submitted, the form data will be submitted to the background together so that the background can obtain the parameters through parsing.

2. Tips for passing parameters by GET and POST methods

When passing parameters, you need to pay attention to the difference between the GET method and the POST method and the security issues. The GET method uses parameters as part of the URL and transmits them in clear text, which can easily be intercepted or tampered by malicious attackers. The POST method includes parameters in the message body of the HTTP request. Although it is more secure, the transmission efficiency is lower.

When passing parameters, you can use some techniques to process parameters to make it more flexible and safe when using the GET or POST method.

1. Use URL encoding to pass parameters

In the GET method, the parameters are displayed in the URL in plain text. If the parameters contain some special characters, such as spaces, Chinese, symbols, etc., Problems will arise. At this time, URL encoding technology needs to be used to encode the parameters so that no exceptions occur during the transmission process. URL encoding works by converting special characters into the hexadecimal representation of %xx. For example, a space is encoded as , and the Chinese "中国" is encoded as China.

In the URL, all special characters need to be encoded. In HTML, URL encoding and decoding can be performed using the encodeURIComponent() and decodeURIComponent() functions, as shown below:

var keyword = "中国";
var url = "http://www.example.com/index.php?keyword=" + encodeURIComponent(keyword);

The above code utilizes The encodeURIComponent() function encodes Chinese, and the generated URL address is:

http://www.example.com/index.php?keyword=%e4%b8%ad%e5%9b%bd

During background processing, the parameters need to be decoded:

$keyword = urldecode($_GET['keyword']);

2. Use hidden form delivery Parameters

When using the POST method to pass parameters, there is a technique to use hidden forms to pass parameters. Hiding a form means setting the style attribute of the form element to display:none to make it invisible on the page. By adding necessary parameters in the hidden form, it can be sent to the background together when the form is submitted.

For example:

<form method="post" action="http://www.example.com/index.php">
    <input type="text" name="keyword" value="中国">
    <input type="hidden" name="id" value="123">
    <input type="submit" name="submit" value="提交">
</form>

In the above code, the type attribute of the <input> tag is hidden, indicating that this is a hidden form,# The ##name attribute represents the parameter name, and the value attribute represents the parameter value. When submitting the form, these parameters will be sent to the background together.

3. Use JSON data format to transfer parameters

JSON is a lightweight data exchange format with the characteristics of versatility, flexibility and readability. In parameter passing, the parameters can be directly encapsulated in a JSON object and then passed through the POST method.

For example:

var data = {"id":123, "name":"中国"};
$.post("http://www.example.com/index.php", JSON.stringify(data), function(response){
    console.log(response);
}, "json");

In the above code, jQuery’s

$.post() function is used to implement the POST method submission. The first parameter of this function represents the page that processes the data, the second parameter represents the data to be sent, the third parameter represents the callback function after success, and the fourth parameter represents the data type.

When processing in the background, you need to use the

json_decode() function in PHP for decoding:

$data = json_decode(file_get_contents('php://input'), true);

这段代码中，file_get_contents('php://input')表示获取提交的消息体，即POST方法中的参数。json_decode()函数将JSON格式的参数解码为PHP数组，第二个参数为true表示转换为关联数组形式。

注意：利用JSON进行参数传递时，需要注意安全性问题，防止恶意攻击者注入JS代码或跨站脚本攻击。此时，可以使用jQuery的$.param()函数将参数序列化为字符串进行安全性处理。

总结：

HTML跳转参数可以通过URL参数或表单提交实现，使用GET方法和POST方法进行参数传递时，需要注意安全性和参数的编码解码问题。可以利用URL编码、隐藏表单或JSON数据格式等技巧来实现参数的传递。

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