JS Form Archives - DW Faisalabad

JavaScript Validation API

Constraint Validation DOM Methods Property Description checkValidity() Returns true if an input element contains valid data. setCustomValidity() Sets the validationMessage property of an input element. If an input field contains invalid data, display a message: The checkValidity() Method <input id=”id1″ type=”number” min=”100″ max=”300″ required> <button onclick=”myFunction()”>OK</button><p id=”demo”></p> <script> function myFunction() { var inpObj = document.getElementById(“id1”); if (!inpObj.checkValidity()) { document.getElementById(“demo”).innerHTML = inpObj.validationMessage; } } </script> Try it […]

JavaScript Forms

JavaScript Form Validation HTML form validation can be done by JavaScript. If a form field (fname) is empty, this function alerts a message, and returns false, to prevent the form from being submitted: JavaScript Example function validateForm() { var x = document.forms[“myForm”][“fname”].value; if (x == “”) { alert(“Name must be filled out”); return false; } } The function can be […]