Alert: Modal Message Box

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Question: How do I display an alert message from JavaScript?

Answer: To display an alert message (a simple modal message box), use the

alert()
method:
window.alert('Message goes here')

The button above was created using the following code:

<form name=myform>
<input type=button value="Try it now" 
onClick="alert('Hello from JavaScript!')">
</form>
Note that
alert()
is a method of the
window
object. Thus, all of the following JavaScript statements produce similar results:
alert('message')
window.alert('message')  // reference to current window
self.alert('message')    // reference to current window
top.alert('message')     // top-level frameset
parent.alert('message')  // parent frame in a  frameset

Returned value. The

alert()
method does not return a value (that is, it returns
undefined
).

See also other JavaScript dialogs:

  • Confirm dialog
  • Prompt dialog
  • Print dialog
  • Find dialog
  • Add Favorite dialog
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