how to take value from html text box using parseint javascript

JavaScript
var myInt = parseInt("10.256"); //10
var myFloat = parseFloat("10.256"); //10.256/* 
 * @param string Required. The value to parse. If this argument is not
 * a string, then it is converted to one using the ToString abstract
 * operation. Leading whitespace in this argument is ignored.
 *
 * radix
 * @param radix Optional. An integer between 2 and 36 that represents
 * the radix (the base in mathematical numeral systems) of the string.
 * Be careful—this does not default to 10!
 * @see https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/parseInt#Description
 * for what happens when radix is not provided
 */
parseInt(string, radix);

console.log(parseInt(' 0xF', 16));
// expected output: 1500

console.log(parseInt('321', 2));
// expected output: 0

console.log(parseInt('321', 10));
// expected output: 321<!-- GET VALUE/INTEGER FROM HTML TEXTBOX/<INPUT> -->

<!-- First set up your input box within the <body> tag -->
<input id="example"> <!-- you are able to set the id to whatever you like,
						just make sure it is unique to your page and is
						understandable -->

<script> <!-- Use this tag within the body to write javascript in -->
  
</script>

<!-- Inside the script tag, use parseInt() to grab value and assign it 
to a variable to use later -->
<script>
  var examplevar = parseInt(document.getElementById("example").value);
</script>
<!-- Make sure to set the identifier/id of the .geteElementBy tag to the id of
the textbox you want to grab the value from, or else it will result in
 an error message. -->

<!-- You now have a variable that can be used for math equations in 
javascript -->
Source

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