Parameter
Message: It is the message that is needed to show in the alert box and it’s optional.
Example: Display an alert box by double-clicking a button.
html
<!DOCTYPE html> < html lang = "en" > < head > < meta charset = "UTF-8" > < meta name = "viewport" content = "width=device-width, initial-scale=1.0" > < title >Document</ title > </ head > < body > < h1 style = "color: green;" > w3wiki </ h1 > < p > For displaying the alert message, double click the "Show Alert Message" button: </ p > < button ondblclick = "myalert()" > Show Alert Message </ button > < script > function myalert() { alert("Welcome to w3wiki.\n " + "It is the best portal for computer" + "science enthusiasts!"); } </ script > </ body > </ html > |
Output:
Example: Alert the hostname of the current URL
HTML
<!DOCTYPE html> < html lang = "en" > < head > < meta charset = "UTF-8" > < meta name = "viewport" content = "width=device-width, initial-scale=1.0" > < title >Alert Hostname Example</ title > </ head > < body style = "text-align: center;" > < h1 style = "color: green;" > Geeks </ h1 > < p > To see the hostname of the current URL, click the "Show Hostname" button: </ p > < button onclick = "showHostname()" > Show Hostname </ button > < script > function showHostname() { let currentURL = window.location.hostname; alert("The hostname of the current URL is: " + currentURL); } </ script > </ body > </ html > |
Output:
HTML DOM Window alert() Method
HTML Window alert() method is used to display an alert box. It displays a specified message along with an OK button and is generally used to make sure that the information comes through the user. It returns a string that represents the text to display in the alert box.
Note: Alert boxes grab your attention and make you read a message and Using too many alerts stops you from doing other things on the webpage until you close them.