Нужно больше функций

index.html

@@ -6,6 +6,7 @@
   <link rel="stylesheet" href="css/normalize.css">
   <link rel="stylesheet" href="css/style.css">
   <link rel="shortcut icon" href="favicon.ico" type="image/x-icon">
+  <script  defer src="js/functions.js"></script>
   <title>Кекстаграм</title>
 </head>
 

js/functions.js

@@ -0,0 +1,20 @@
+function checkLengthString(string = '', number = 1) {
+  return string.length <= number;
+}
+
+function isPalindrome(string = '') {
+  const normalizeString = string.replaceAll(' ', '').toLowerCase();
+  const reverseString = normalizeString.split('').reverse().join('');
+  return normalizeString === reverseString;
+}
+
+function getNumbers(string = '') {
+  const str = String(string);
+  let result = '';
+  for(const sign of str) {
+    if(sign >= '0' && sign <= '9') {
+      result += sign;
+    }
+  }
+  return parseInt(result, 10);
+}