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A brief analysis of how to implement the function of clicking a button to save query conditions in PHP
- PHPzOriginal
- 2023-04-04 10:43:04673browse
In the search page of the website, we often need to implement the function of clicking a button to save query conditions. As a programming language, PHP can easily implement this function. In this article, we will introduce how to implement the function of clicking a button to save query conditions in PHP.
1. Problem Description
In the search pages of many websites, we can see some buttons, such as the "Save Query Conditions" button. The function of this button is to save the current search conditions so that when searching again in the future, these conditions can be loaded directly without re-entering.
2. Solution
There are many ways to implement this function, but in this article we will use PHP session to achieve it. Session is a technology that stores information on the server side. You can achieve persistent storage of user data by setting session variables. When the user closes the browser, the session will be automatically destroyed. Below we will introduce how to use PHP session to realize the function of clicking a button to save query conditions.
- Create a search page
First, we need to create a search page, including some search conditions and a "Save Query Conditions" button, as shown below:
<html> <head> <title>搜索页面</title> </head> <body> <form method="get" action="result.php"> <label>关键字：</label> <input type="text" name="keyword"><br> <label>日期：</label> <input type="date" name="date"><br> <label>类型：</label> <select name="type"> <option value="1">新闻</option> <option value="2">论文</option> <option value="3">博客</option> </select><br> <input type="submit" value="搜索"> <input type="button" value="保存查询条件" onclick="saveSearch()"> </form> </body> </html>
In this page, we use the HTML form tag to create a search form, and use some HTML elements to enter search conditions. Note that in the last input tag, we set an onclick event. When the user clicks the "Save Query Conditions" button, this event will trigger a JavaScript function saveSearch().
- Writing JavaScript function
In the previous step, we set up the onclick event, which will trigger a JavaScript function saveSearch(). Let's implement this function. The function of this function is to save the current search conditions into the PHP session.
<script>
function saveSearch() {
var keyword = document.getElementsByName("keyword")[0].value;
var date = document.getElementsByName("date")[0].value;
var type = document.getElementsByName("type")[0].value;
var search = {"keyword": keyword, "date": date, "type": type};
var searchStr = JSON.stringify(search);
sessionStorage.setItem("search", searchStr);
}
</script>
In this function, we first obtain the search conditions entered by the user, and then save them into a JavaScript object search. Next, we use JSON.stringify to convert this object into a JSON string and save it to the PHP session with the name "search".
- Load search conditions
When the user searches again, we need to load the previously saved search conditions from the PHP session. We can add a piece of PHP code to the search results page to load these conditions:
<?php
session_start();
if (isset($_SESSION['search'])) {
$search = json_decode($_SESSION['search'], true);
$keyword = $search['keyword'];
$date = $search['date'];
$type = $search['type'];
}
?>
In this code, we first call the session_start() function to open the session, and then determine $_SESSION['search'] does it exist. If it exists, it means that the search conditions have been saved before. We use json_decode to convert the saved JSON string into a PHP array and get the keywords, date and type from it. These values can be used to initialize input and select boxes in search forms.
- Using loaded search criteria
Finally, we need to use the loaded search criteria to perform the search operation. We can add a JavaScript function initSearch() in the form tag of the search page to initialize the search conditions:
<script>
function initSearch() {
<?php
if (isset($keyword)) {
echo "document.getElementsByName('keyword')[0].value = '$keyword';";
}
if (isset($date)) {
echo "document.getElementsByName('date')[0].value = '$date';";
}
if (isset($type)) {
echo "document.getElementsByName('type')[0].value = '$type';";
}
?>
}
</script>
This function will be executed when the page is loaded, and the value of the search conditions will be assigned to the corresponding input box and Select box. We only need to add an onload event to the form tag:
<form method="get" action="result.php" onload="initSearch()">
In this way, when the user accesses the search page, if the search conditions have been saved before, these conditions will be initialized to the corresponding input box and selection boxes, users can use them directly for search operations.
3. Summary
This article introduces how to save search conditions through PHP session. During the next search, the saved conditions are directly loaded so that users can quickly perform search operations. This function is very helpful for users' search experience, reducing the number of user inputs and improving user satisfaction.
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