How to add a special character to A Password Validation Form

var myInput = document.getElementById("password");
var letter = document.getElementById("letter");
var capital = document.getElementById("capital");
var number = document.getElementById("number");
var length = document.getElementById("length");
var special = document.getElementById("special");

// When the user clicks on the password field, show the message box
myInput.onfocus = function() {
    document.getElementById("message").style.display = "block";
}

// When the user clicks outside of the password field, hide the message box
myInput.onblur = function() {
    document.getElementById("message").style.display = "none";
}

// When the user starts to type something inside the password field
myInput.onkeyup = function() {
// Validate lowercase letters
var lowerCaseLetters = /[a-z]/g;
if(myInput.value.match(lowerCaseLetters)) {  
letter.classList.remove("invalid");
letter.classList.add("valid");
} else {
letter.classList.remove("valid");
letter.classList.add("invalid");
}

// Validate capital letters
var upperCaseLetters = /[A-Z]/g;
if(myInput.value.match(upperCaseLetters)) {  
capital.classList.remove("invalid");
capital.classList.add("valid");
} else {
capital.classList.remove("valid");
capital.classList.add("invalid");
}

// Validate numbers
var numbers = /[0-9]/g;
if(myInput.value.match(numbers)) {  
number.classList.remove("invalid");
number.classList.add("valid");
} else {
number.classList.remove("valid");
number.classList.add("invalid");
}

// Validate length
if(myInput.value.length >= 8) {
length.classList.remove("invalid");
length.classList.add("valid");
} else {
length.classList.remove("valid");
length.classList.add("invalid");
}

// Validate special
var specialcharacters = /[`!@#$%^&*()_+-=[]{};':"\|,.<>/?~]/g;
if(myInput.value.match(specialcharacters)) {
special.classList.remove("invalid");
special.classList.add("valid");
} else {
special.classList.remove("valid");
special.classList.add("invalid");
}
}

<style>
#message {
display:none;
background: #EFEFEF;
color: #000;
position: relative;
margin-top: 0px;
text-align:left;
width:100%;
}
#message p {
padding: 2px 35px 2px 60px;
font-size: 18px;
}
/* Add a green text color and a checkmark when the requirements are right */
.valid {
color: green;
}
.valid:before {
position: relative;
left: -20px;
content: "✔";
}
/* Add a red text color and an "x" when the requirements are wrong */
.invalid {
color: red;
}
.invalid:before {
position: relative;
left: -20px;
content: "✖";
color: red;
}
</style>

<form>
<input type="password" name="password" placeholder="Password" id="password" required minlength="8" maxlength="32" pattern="(?=.*d)(?=.*[a-z])(?=.*[A-Z]).{8,}">
</form>

<div id="message">
<div style="padding-top:8px;"></div>
<h2 style="padding-left:40px;font-size:19px;text-decoration:underline;font-weight:650;color:#333;">Password Requirements:</h2>
<p id="letter" class="invalid"><span style="font-weight:600;font-size:17px;">A lowercase letter</span></p>
<p id="capital" class="invalid"><span style="font-weight:600;font-size:17px;">A capital letter</span></p>
<p id="number" class="invalid"><span style="font-weight:600;font-size:17px;">A number</span></p>
<p id="special" class="invalid"><span style="font-weight:600;font-size:17px;">A special character</span></p>
<p id="length" class="invalid"><span style="font-weight:600;font-size:17px;">A minimum of 8 characters</span></p>
</div>