Canceled prompt

JavaScript FAQ | JavaScript Dialogs FAQ  

Question: What value does

prompt()
return if the user clicked the Cancel button?

Answer: The return value of canceled

prompt()
depends on the browser. In most browsers the return value is
null
; however, some very old browsers (e.g. early versions of IE) used to return
''
(an empty string).

Therefore, when calling

prompt()
, you may want to use an
if
statement like this:
userInput = prompt('Prompt text','Suggested input');
if (userInput != '' && userInput != null) {
 // do something with the input
}

This code can be simplified to:

userInput = prompt('Prompt text','Suggested input');
if (userInput) {
 // do something with the input
}

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