Let's talk about the branch selection process in Jquery-Front-end Q&A-php.cn

Let's talk about the branch selection process in Jquery

PHPz

Release： 2023-04-26 15:37:02

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With the rapid development of Internet technology, front-end development technology has also continued to innovate, among which Jquery technology has become one of the most popular front-end frameworks. Jquery has good cross-browser support, is simple and easy to learn, has a rich plug-in library and powerful DOM manipulation capabilities. In this article, we will introduce the branch selection process in Jquery to help you better master this technology.

1. Jquery branch selector

1.1 if statement

The if statement in Jquery can be used to perform branch selection based on judgment conditions. The syntax is as follows:

if (condition) {
  // code block to be executed if condition is true
} else {
  // code block to be executed if condition is false
}

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Among them, condition represents the condition to be judged. If the condition is met, the code block in the if conditional statement will be executed, otherwise the code block in the else statement will be executed.

1.2 switch statement

The switch statement in Jquery can be used to perform branch selection based on multiple judgment conditions. The syntax is as follows:

switch (expression) {
  case value1:
    // code block to be executed if expression is equal to value1
    break;
  case value2:
    // code block to be executed if expression is equal to value2
    break;
  default:
    // code block to be executed if expression is neither value1 nor value2
}

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Among them, expression represents the expression to be judged. If the value of the expression is equal to the value in a case statement, the code block in the case statement will be executed. Otherwise, default will be executed. A block of code within a statement.

2. Sample code

The following is a sample code that demonstrates the branch selection process in Jquery:

Suppose we have the following HTML code:

<!DOCTYPE html>
<html>
<head>
    <title>Jquery 分支选择流程示例</title>
    <script src="https://ajax.googleapis.com/ajax/libs/jquery/3.5.1/jquery.min.js"></script>
</head>
<body>

    <button id="btn1">点击我</button>

    <script>
        $(document).ready(function(){
            $("#btn1").click(function(){
                var x = Math.floor((Math.random() * 10) + 1);
                if (x < 5) {
                    alert("x 的值小于 5");
                } else {
                    alert("x 的值大于等于 5");
                }
            });
        });
    </script>

</body>
</html>

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When we click the button, the Jquery code will be executed. This code will generate a random number x between 1 and 10. If the value of x is less than 5, a prompt box of "The value of x is less than 5" will pop up; otherwise, a prompt box of "The value of prompt box.

3. Conclusion

Through the introduction of this article, we have learned about the branch selection process in Jquery. The if statement and switch statement are the most basic branch selectors in Jquery, which can help us make branch selections based on different conditions. In actual development, we can use these statements to optimize code logic and improve code execution efficiency according to specific business needs.

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