JavaScript study notes (16) System dialog box (alert, confirm, prompt)_Basic knowledge

1. Warning box alert()

Copy code The code is as follows:

alert("Welcome !");

2. Information box confirm(), with cancel and OK buttons

Copy code The code is as follows:

if (confirm("Do you agree?")) {
alert("Agree");
} else {
alert("No Agree");
}

3. Prompt box prompt(), used to prompt the user to enter some text

Copy code The code is as follows:

var result = prompt("What is your surname?"," ");
if (result !== null) {
alert(“Welcome,” result);
}