JavaScript: Escapes special characters for use in HTML

Last update on May 30 2022 10:00:27 (UTC/GMT +8 hours)

JavaScript String: Exercise-31 with Solution

Write a JavaScript function to escapes special characters (&, <, >, ', ") for use in HTML.

Test Data:
console.log(escape_html('PHP & MySQL'));
"PHP & MySQL"
console.log(escape_html('3 > 2'));
"3 > 2"

Sample Solution:-

HTML Code:

<!DOCTYPE html>
<html>
<head>
  <meta charset="utf-8">
  <title>JavaScript function to escapes special characters for use in HTML.</title>
</head>
<body>

</body>
</html>

JavaScript Code:

function escape_html(str) {
  
 if ((str===null) || (str===''))
       return false;
 else
   str = str.toString();
  
  var map = {
    '&': '&amp;',
	'<': '&lt;',
	'>': '&gt;',
	'"': '&quot;',
	"'": '&#039;'
  };

  return str.replace(/[&<>"']/g, function(m) { return map[m]; });
}
console.log(escape_html('PHP & MySQL'));
console.log(escape_html('3 > 2'));

Sample Output:

PHP & MySQL
3 > 2

Flowchart:

Live Demo:

See the Pen JavaScript Escapes special characters for use in HTML - string-ex-31 by w3resource (@w3resource) on CodePen.

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JavaScript: Tips of the Day

How to insert an item into an array at a specific index (JavaScript)?

What you want is the splice function on the native array object.

arr.splice(index, 0, item); will insert item into arr at the specified index (deleting 0 items first, that is, it's just an insert). In this example we will create an array and add an element to it into index 2:

var arr = [];
arr[0] = "Jani";
arr[1] = "Hege";
arr[2] = "Stale";
arr[3] = "Kai Jim";
arr[4] = "Borge";

console.log(arr.join());
arr.splice(2, 0, "Lene");
console.log(arr.join());

Ref: https://bit.ly/2BXbp04