Learn how to implement form validation in JavaScript to display an error message when required fields are left empty upon form submission. Enhance your web development skills with this interactive JavaScript program.
setCustomValidity()Sets the validationMessage property of an input element. If an input field contains invalid data, display a message: The checkValidity() Method OK <pid="demo"> functionmyFunction() { constinpObj = document.getElementById("id1"); if(!inpObj...
Click the following button to see the result: Click Me Error: Uncaught ReferenceError: myFunc is not defined URL: file:///C:/Users/Lenovo/Desktop/intex.html Line: 5 You can use an onerror method, as shown below, to display an error message in case there is any problem in loading an ...
DOCTYPE html> Form Validation .error { border: 1px solid red; } .error-message { color: red; display: none; } Username is required. Valid email is required. Submit
var btnsubmit = document.querySelector('input[type="submit"]');btnsubmit.addEventListener("click", function(event){ console.log(email.validationMessage); console.log(email.checkValidity()); // false // customError: true, valueMissing: true, valid: false console.log(email.validity...
document.getElementById('prompt').innerHTML = myInput.validationMessage; } 3.5、setCustomValidity() 控件元素的setCustomValidity()方法用来定制校验失败时的报错信息。它接受一个字符串作为参数,该字符串就是定制的报错信息。如果参数为空字符串,则上次设置...
In this example we have written "alert" as "adddlert" to deliberately produce an error. Return the error name and a description of the error: try { adddlert("Welcome");}catch(err) { document.getElementById("demo").innerHTML = err.name + "" + err.message;} Try it Yourself » ...
validationMessage (显示验证异常信息) setCustomValidity(message) (自定义验证错误信息) 自定义异常范例 涉及到的知识点: AI检测代码解析 oninvalid setCustomValidity 1. 2. AI检测代码解析 Name: submit input.addEventListener( 'invalid', function(event){ var target = event.target; ...
try { // Code that may throw an error } catch (error) { // Code to handle the error console.error(error.message); }Code language: JavaScript (javascript) Example with Array: try { let arrayLength = -5; let myArray = new Array(arrayLength); // This will throw a RangeError } ca...
3.4、validationMessage 属性 控件元素的validationMessage属性返回一个字符串,表示控件不满足校验条件时,浏览器显示的提示文本。以下两种情况,该属性返回空字符串。 该控件不会在提交时自动校验 该控件满足校验条件 // HTML 代码如下