In jQuery, the toggle() function is used to hide and show elements.

Here's an example of how to use it:

javascript
 
 
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// HTML
<button>Toggle Element</button>
<p>Hello, I will be toggled!</p>

// JavaScript/jQuery
$("button").on("click", function() {
  $("p").toggle();
});

In this example, clicking the button will toggle the visibility of the <p> element. If it's hidden, it will be shown. If it's shown, it will be hidden.

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import React, { useState, useEffect } from "react";

function App() {
  const [showButton, setShowButton] = useState(true);

  useEffect(() => {
    const handleResize = () => {
      if (window.innerWidth < 768) {
        setShowButton(false);
      } else {
        setShowButton(true);
      }
    };

    window.addEventListener("resize", handleResize);
    return () => window.removeEventListener("resize", handleResize);
  }, []);

  return (
    <div>
      {showButton && <button>Click me!</button>}
    </div>
  );
}

This code snippet uses the useState hook to create a boolean state variable showButton which controls whether or not the button is displayed.

The useEffect hook is used to add a listener for the resize event on the window object. Whenever the window is resized, the handleResize function is called which checks the window width and sets the showButton state accordingly.

The return function inside the useEffect hook is used to remove the event listener when the component unmounts, and prevent memory leaks.

Finally, the showButton state is used to conditionally render the button. The button is only displayed if showButton is true.

To hide a button in React, you can use the style attribute and set the display property to "none". This can be done inline or by adding it to a CSS file and referencing the class in your button element.

Here is an example of hiding a button inline:

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import React from 'react';

function App() {
  return (
    <div>
      <button style={{ display: "none" }}>Hidden Button</button>
    </div>
  );
}

export default App;

Note: If you want to show/hide the button dynamically based on some condition, you can store a boolean variable in state and conditionally render the button based on its value.

Here is an example:

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import React, { useState } from 'react';

function App() {
  const [showButton, setShowButton] = useState(true);

  const toggleButton = () => {
    setShowButton(!showButton);
  };

  return (
    <div>
      {showButton && <button onClick={toggleButton}>Hide Button</button>}
    </div>
  );
}

export default App;

In the above example, initially the button is shown. When the button is clicked, the toggleButton function is called which toggles the value of showButton in state, making it false and hiding the button.

In JavaScript, you can use the style.display property to hide and show an HTML element. For example:

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document.getElementById("myDiv").style.display = "none"; //hide
document.getElementById("myDiv").style.display = "block"; //show

You can find more information about the style.display property here: https://www.w3schools.com/jsref/prop_style_display.asp

HTML:

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<div id="modalWindow" style="display: none;">
  <div>
    <div>
      <p>Modal content here.</p>
    </div>
    <div>
      <input type="button" value="Close" onclick="hideModal()" />
    </div>
  </div>
</div>

CSS:

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#modalWindow {
  position: fixed;
  top: 0;
  bottom: 0;
  left: 0;
  right: 0;
  background: rgba(0, 0, 0, 0.7);
  margin: auto;
  padding: 10px;
  width: 500px;
  font-family: arial;
  font-size: 14px;
  text-align: center;
}

JavaScript:

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// reads the DOM element
let modalWindow = document.querySelector('#modalWindow');

// shows the modal window
function showModal() {
  modalWindow.style.display = 'block';
}

// hides the modal window
function hideModal() {
  modalWindow.style.display = 'none';
}