How to pop up query box in javascript

In web development, JavaScript is a powerful scripting language that can add various interactive functions to web pages. Among them, the pop-up query box is a very common interactive operation, which allows users to search and query conveniently. This article will introduce how to use JavaScript to pop up a query box.

To pop up the query box in the web page, you can use the prompt() function in JavaScript. This function can receive two parameters. The first parameter is a string, representing the prompt text of the pop-up box; the second parameter is a string, representing the default value of the input box. The following is a simple example:

var result = prompt("请输入您的姓名：", "");

In this example, we define a variable result, and use the prompt() function to pop up a query box to allow the user to enter a name. The first parameter of the function is the prompt text, and the second parameter is the default value of the input box. Here we set the default value to an empty string. When the user clicks the OK button, the function returns a string representing the result of the user's input. If the user clicks the cancel button, the function will return null.

After getting the results input by the user, we can process them according to specific needs. For example, if we need to display the content entered by the user on the web page, we can use the following code:

document.write("您输入的姓名是：" + result);

This code uses the document object and string splicing symbol ( ) in JavaScript to display the content entered by the user. The results are displayed on the web page.

In addition to using the prompt() function, you can also use other pop-up box functions, such as alert() and confirm(). These two functions are similar to the prompt() function. They can also receive a string as a parameter and display a pop-up box. The difference is that the alert() function has only one "OK" button for displaying a message, while the confirm() function has two "OK" and "Cancel" buttons for confirming or canceling an operation. The following is an example of using the alert() and confirm() functions:

alert("欢迎来到我的网站！");
var result = confirm("您确定要删除这个文件吗？");

In this example, we first use the alert() function to pop up a welcome message, and then call the confirm() function to pop up a confirmation box to let the user Confirm whether you want to delete a file. Depending on the user's selection, the function returns true or false.

In general, the pop-up box function in JavaScript is a very convenient and practical way of interaction, which can help us achieve various interactive effects. Use the prompt() function to implement a pop-up query box, and use the alert() and confirm() functions to implement pop-up message boxes and confirmation boxes. Of course, in practical applications, we need to flexibly choose the appropriate pop-up box function based on specific needs.

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