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In JavaScript, you can use the prompt() method of the Window object to implement a prompt box. This method can pop up a prompt box with an input box, an "OK" button and a "Cancel" button. The syntax is "prompt("sometext","defaultText")".
The operating environment of this tutorial: Windows 10 system, JavaScript version 1.8.5, Dell G3 computer.
If you want the user to enter a value before entering the page, you will usually use a prompt box.
When the prompt box pops up, the user will have to enter a value and click "OK" or click "Cancel" to continue.
If the user clicks "OK", the box returns the input value. If the user clicks Cancel, this box returns NULL.
The syntax is:
window.prompt("sometext","defaultText");The window.prompt() method can be written without the window prefix.
The example is as follows:
<html>
<body>
<h1>JavaScript Prompt</h1>
<button onclick="myFunction()">试一试</button>
<p id="demo"></p>
<script>
function myFunction() {
var txt;
var person = prompt("请输入您的名字：", "哈利波特");
if (person == null || person == "") {
txt = "用户取消输入";
} else {
txt = "你好，" + person + "！今天过得好吗？";
}
document.getElementById("demo").innerHTML = txt;
}
</script>
</body>
</html>Output result:
javascript video tutorial, web front-end】
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