Alert javascript not defined

ReferenceError: «alert» is not defined

When click on it, alert come up. and to test it; but this test gives alert error. please help me to fix this error. See option devel for more information. and the following about the option: This option defines globals that are usually used for logging poor-man’s debugging: console, alert, etc.

ReferenceError: «alert» is not defined

I am trying to call a java script function from java code .

 public static void main(String[] args) throws FileNotFoundException < try < /** * To call a anonymous function from java script file */ ScriptEngine engine = new ScriptEngineManager() .getEngineByName("javascript"); FileReader fr = new FileReader("src/js/MySpec.js"); engine.eval(fr); >catch (ScriptException scrEx) < scrEx.printStackTrace(); >> 

But when I run main method of driver class it is giving me error as below:

Exception in thread "main" javax.script.ScriptException: sun.org.mozilla.javascript.internal.EcmaError: ReferenceError: "alert" is not defined. (#2) in at line number 2 at com.sun.script.javascript.RhinoScriptEngine.eval(RhinoScriptEngine.java:110) at javax.script.AbstractScriptEngine.eval(AbstractScriptEngine.java:232) at Java6RhinoRunner.load(Java6RhinoRunner.java:42) at Java6RhinoRunner.main(Java6RhinoRunner.java:12) 

What I know is that it need some script engine to execute it.

For that I added rhino.jar file in to my class path.But this is not working.

I an not getting how to solve this error. Please help.Thanks in advance.

alert is not part of JavaScript, it’s part of the window object provided by web browsers. So it doesn’t exist in the context you’re trying to use it in. (This is also true of setInterval , setTimeout , and other timer-related stuff, FYI.)

If you just want to do simple console output, Rhino provides a print function to your script, so you could replace alert with print . Your script also has access to all of the Java classes and such, so for instance java.lang.System.out.println(‘Hello’); would work from your JavaScript script (although it’s a bit redundant with the provided print function). You can also make Java variables available to your script easily via ScriptEngine.put , e.g:

out.println('Hello from JavaScript'); 

. so that’s a third way to do output from the script. 🙂

See the discussion in the javax.script package documentation, in particular ScriptEngine#put , or for more complex cases, Bindings (and SimpleBindings ) and ScriptContext .

Uncaught ReferenceError: function is not defined with, For the loop, you can’t pass data to an event listener like that See the doc.Plus every time you change innerHTML like that, you destroy the previous event listeners!. Without refactoring your code much, …

Javascript:alert(‘. ‘) — Error: uncaught exception: ReferenceError: alert is not defined [duplicate]

Possible Duplicate:
JavaScript alert not working in Firefox 6

I often execute Javascript code in the address bar (mostly for debugging and testing): javascript:alert(some_function_with_interesting_return_value(‘blah’)); Or — more obvious: javascript:alert(‘interesting value’);

This doesn’t seem to work anymore with Firefox 6: Error: uncaught exception: ReferenceError : alert is not defined

How is it possible for alert() not to be defined ?

I’ve double-checked it with Firefox 5, Epiphany, Midori and Chromium — works fine.

I think it’s maybe prevention, because a lot of sites abused this.

FYI, I’m probably going to split this bug into multiple, short and longer term fixes.

Short term: disallow pasting of javascript: URLs into the URL bar Longer term: additionally require that bookmarklets be «whitelisted» in the Bookmark Manager before it can run JavaScript

Javascript — how to get rid of ReferenceError: window is, I have just started learning JavaScript and i am using Atom text editor, and installed NodeJS v14.7.0 version. I have written only one line of code which is:— window.alert("Hello MySelf"

«alert» is not defined when running www.jshint.com

I fixed this by simply adding var alert; However, is this what I should be doing to get the pesky error message to go away? Here is the fix. Here is the fail on www.jshint.com.

I’m trying to learn from the error it throws..not necessarily make them go away.

(function () < "use strict"; var alert; // added this in to fix function initialize_page() < alert ("hi"); >addEventListener('load', initialize_page); >)(); 

Because this method is defined in window object.

This of course assumes you have browser option set to true in your .jshintrc , so this way jshint will know window object is exposed.

"browser" : true, // Standard browser globals e.g. window, document. 

*The same thing happens with confirm() .

This documentation says the following about the browser option:

This option defines globals exposed by modern browsers: all the way from good ol’ document and navigator to the HTML5 FileReader and other new developments in the browser world. Note: this option doesn’t expose variables like alert or console. See option devel for more information.

and the following about the devel option:

This option defines globals that are usually used for logging poor-man’s debugging: console, alert, etc. It is usually a good idea to not to ship them in production because, for example, console.log breaks in legacy versions of Internet Explorer.

You have browser enabled and devel disabled. You can control these with checkboxes under «Assume» on the jshint original page. I also recommend heeding the warning in the documentation 😉

Set «devel:true» in the Options. This enables things like Alert, console, etc.

See documentation here: http://jshint.com/docs/options/

Use .jshintrc file or CTRL + , in VS Code , to edit options for jshint .

in js alert(data.status); or window.alert(data.status);

Javascript — ReferenceError: term is not defined, ReferenceError: term is not defined. I have a page that only allows the user to click search — I added a section to prevent them from sending empty requests but I seem to have messed up when combining that with my existing code. Now when I click search in the console logs I see the error: ReferenceError: term …

Jest test fail, alert is not defined

I use jest for my react native project, I want to test the component which has «onPress». When click on it, alert come up.

it('test onPress functionality', () => < window.alert = jest.fn(); const wrapper = shallow( />, ); wrapper .findWhere(node => node.prop('testID') === 'Contact') .props() .onPress(); expect(window.alert).toHaveBeenCalledWith('hello'); >); 

but this test gives alert error.

ReferenceError: alert is not defined onPress= alert(‘hello’)>

please help me to fix this error.

import from 'react-native'; onPress= Alert.alert('hello')> /> 

Your **** incorrect, as you’re testing for ‘onPress’ being the argument.

expect(window.alert).toHaveBeenCalledWith('hello'); 

This might not be fully related but I was getting the «not defined» error from eslint using react.js . My solution was to explicitly replace all instances of «alert» with «window.alert» and eslint fully accepted it

Javascript undefined error: ReferenceError: ALT is not, Thanks for contributing an answer to Stack Overflow! Please be sure to answer the question.Provide details and share your research! But avoid …. Asking for help, clarification, or responding to other answers.

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Alert javascript not defined

Last updated: Dec 28, 2022
Reading time · 4 min

# Table of Contents

# ReferenceError: Alert is not defined in JavaScript

The «ReferenceError: alert is not defined» occurs when the alert() method is used outside of the browser environment, most commonly in Node.js.

The alert() method is a method on the window object, which is only available in the browser.

# Use console.log when outside the browser

To solve the «alert is not defined» error, use the console.log or console.error methods instead of alert when outside the browser.

The console.log and console.error methods allow us to output a message to the web console or standard output and error if you’re on the server side.

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console.log('hello'); console.error('an error occurred'); 

If you use a console.log() statement in a browser environment, open your developer tools by pressing F12 and click on the Console tab to view the output.

If you use a console.log() statement on the server, look at your terminal to view the output if you have a server running or run your script with node yourScript.js and then look at your terminal.

# Checking if you are on the browser or the server

If you got the error in a browser, you might be using server-side rendering (e.g. with Next.js), or you might have misspelled alert (all lowercase).

If you got the error when using server-side rendering, you can conditionally check if you’re on the browser (can use alert ) or you are on the server (can’t use alert ).

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if (typeof window !== 'undefined')  console.log('You are on the browser') // 👉️ can use alert() > else  console.log('You are on the server') // 👉️ can't use alert() > 

In our if statement, we check if the window global variable is not undefined . If it is defined, we can use the alert method.

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console.log(alert === window.alert); // 👉️ true 

If we check whether alert is equal to window.alert in a browser environment, we get true back.

The window global variable represents the window that contains the DOM (browser side only).

An easy way to think about it is that in a browser, each tab is represented by its own Window object.

# ReferenceError: Prompt is not defined in JavaScript

You might also get the ReferenceError: Prompt is not defined error when you try to use the prompt() method outside the browser.

To resolve the issue, check if you are on the browser before calling window.prompt() or use the prompt-sync package.

Here is an example of how the error occurs.

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const result = prompt('What is your favorite number?'); console.log(result); 

If you issue the node index.js command, I get the following error:

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ReferenceError: prompt is not defined 

The error is caused because the prompt method is available on the window object and not in Node.js.

The prompt() method is used to display a dialog with a message in the browser and prompt the user to enter some text.

The method returns a string containing the text that was entered by the user or null if the user didn’t enter any text.

# Checking if you are on the Browser

If you use Next.js or other similar client and server-side technologies, you can check if you are on the browser or the server using the typeof operator.

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if (typeof window !== 'undefined')  const result = prompt('What is your favorite number?'); console.log(result); > 

Since the prompt() method is only available on the browser, we first check if the window variable is defined.

If the variable is defined, we can safely call the method.

In all other cases, we are on the server, so trying to call the window.prompt() method would raise a ReferenceError .

# Using the prompt() method on the server in Node.js

You can use a third-party package to be able to use the prompt() method in Node.js.

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# with NPM npm install prompt-sync # or with YARN yarn add prompt-sync 

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// using ES6 import statement import createPrompt from 'prompt-sync'; const prompt = createPrompt(); const result = prompt('What is your favorite number: '); console.log(result); 

If you use the older require() syntax, import the prompt-sync module as follows.

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// using commonJS require() statement const createPrompt = require('prompt-sync'); const prompt = createPrompt(); const result = prompt('What is your favorite number: '); console.log(result); 

The prompt-sync package enables us to use the prompt() method in a Node.js environment.

You can read more about the module’s API and its configuration options in its NPM Readme page.

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