In this Article, You will learn How to Validate Form By Using RegExp In JavaScript. In this, I have validate form by using Regular Expression in JQuery & used Javascript to show & hide password, where when user type password & want to see that then user can click on eye icon to see their password & to hide it again user will again on same eye icon to hide it.

SOURCE CODE DOWNLOAD For Demo & Source Code Scroll down.

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Form validation will active when user click on Submit button where id="submit_form" will call click function(). In JavaScrip file, Where all code for validation will call & get the value of all field by using $.trim($("#id").val()); or Val() of JQuery.

In this, I have validate all fields of form. But before starting validation we need to first assume the criteria for validation. It means that we must specify that what we need that user will type the same else it will show error.

As for Password Field, I have Validate that field according to below criteria -

1. Make a strong password

2. Password should be 8 characters long

3. Including a uppercase letter

4. Including a number

5. And one special character such as !@#$%^&*

var passwordregex = /^(.{0,7}|[^0-9]*|[^A-Z]*|[a-zA-Z0-9]*)$/;

When user enter password & click on submit button. Javascript file will call where passwordregex will match with Password entered by user. If the password match with passwordregex it means password is valid & if not it will show Error Message

Now, Password Validation is done. Its time to validate Email Field of form by using Regular Expression Method also known as RegExp.

var emailRegex = new RegExp(/^(("[\w-\s]+")|([\w-]+(?:\.[\w-]+)*)|("[\w-\s]+")([\w-]+(?:\.[\w-]+)*))(@((?:[\w-]+\.)*\w[\w-]{0,66})\.([a-z]{2,6}(?:\.[a-z]{2})?)$)|(@\[?((25[0-5]\.|2[0-4][0-9]\.|1[0-9]{2}\.|[0-9]{1,2}\.))((25[0-5]|2[0-4][0-9]|1[0-9]{2}|[0-9]{1,2})\.){2}(25[0-5]|2[0-4][0-9]|1[0-9]{2}|[0-9]{1,2})\]?$)/i);

Same for Email Validation. When user will enter email & submit form. emailRegex will call & match user entered email with that & if everything is good it will be submitted otherwise it show error message

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Wen user enter password & wish to see then user will click on eye-icon & password become visible again to hide it is user click on same icon password will hide. Its a toggle functionality on icon.

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<div class="input-group" style="margin-bottom: 10px;"> <label for="txtPassword">Password</label> <input type="password" id="txtPassword" class="form-control" name="txtPassword" /> <button type="button" id="btnToggle" class="toggle"> <i id="eyeIcon" class="fa fa-eye"></i> </button> </div>

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function togglePassword() { if (passwordInput.type === "password") { passwordInput.type = "text"; icon.classList.add("fa-eye-slash"); } else { passwordInput.type = "password"; icon.classList.remove("fa-eye-slash"); } }

Here, it will match if input[type] is password then it will swap it to text to make password visible in text form again to hide it when user click on that icon then again JS will match input[type] is Text is will change to type password to hide it.

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let passwordInput = document.getElementById("txtPassword"), toggle = document.getElementById("btnToggle"), icon = document.getElementById("eyeIcon"); function togglePassword() { if (passwordInput.type === "password") { passwordInput.type = "text"; icon.classList.add("fa-eye-slash"); } else { passwordInput.type = "password"; icon.classList.remove("fa-eye-slash"); } } toggle.addEventListener("click", togglePassword, false); passwordInput.addEventListener("keyup", checkInput, false); $("#submit_form").click(function() { var passwordregex = /^(.{0,7}|[^0-9]*|[^A-Z]*|[a-zA-Z0-9]*)$/; var emailRegex = new RegExp( /^(("[\w-\s]+")|([\w-]+(?:\.[\w-]+)*)|("[\w-\s]+")([\w-]+(?:\.[\w-]+)*))(@((?:[\w-]+\.)*\w[\w-]{0,66})\.([a-z]{2,6}(?:\.[a-z]{2})?)$)|(@\[?((25[0-5]\.|2[0-4][0-9]\.|1[0-9]{2}\.|[0-9]{1,2}\.))((25[0-5]|2[0-4][0-9]|1[0-9]{2}|[0-9]{1,2})\.){2}(25[0-5]|2[0-4][0-9]|1[0-9]{2}|[0-9]{1,2})\]?$)/i ); var username = $.trim($("#username").val()); var email = $.trim($("#email").val()); var Password = $.trim($("#txtPassword").val()); $("#username_error").html(""); $("#txtPassword_error").html(""); $("#email_error").html(""); if (username == "") { $("#username").focus(); $("#username_error").show(); $("#username_error").html("Please Enter Username"); return false; } else if (email == "") { $("#email").focus(); $("#email_error").show(); $("#email_error").html("Please Enter Email"); return false; } else if (!email.match(emailRegex)) { $("#email").focus(); $("#email_error").show(); $("#email_error").html("Enter Valid Email"); return false; } else if (Password == "") { $("#txtPassword").focus(); $("#txtPassword_error").show(); $("#txtPassword_error").html("Please Enter Password"); return false; } else if (Password.match(passwordregex)) { $("#txtPassword-field").focus(); $("#txtPassword_error").show(); $("#txtPassword_error").html( "Make a strong password, 8 characters, including a uppercase letter, number and one special character." ); return false; } else { alert("wefw"); } });

You will get all files, when you download the source code. And after than you can edit it according to you

if you face any issues you can contact by asking question with article link.

You can go through Demo as well as Download source code for the same & make changes according to you