One of the features of HTML5 is the ability to validate most user data without relying on scripts.This is done by using validation attributes on form elements, which allow you to specify rules for a form input like whether a value needs to be filled in, the minimum and maximum length of the data, whether it needs to be a number, an email address, or something else, and a pattern that it must match.
You do not have to disable the Form’s Auto Validate property.
However, I prefer to call it explicitly and handle all validation at once since you most likely will take action only if the entire control’s children pass validation. The most important thing to recognize here is how precise you can be with the validation error message in the error provider.
This is called form validation — when you enter data, the web application checks it to see that the data is correct.
If correct, the application allows the data to be submitted to the server and (usually) saved in a database; if not, it gives you an error message explaining what corrections need to be made.
Let’s assume when we click our save button that we wish to validate the controls and display an icon if there is a problem.
First, add the following code to the Form’s constructor after the Initialize Component method: This is a handy trick to prevent implicit validation of our controls when they lose focus.Form validation helps us to ensure that users fill out forms in the correct format, making sure that submitted data will work successfully with our applications.This article will tell you what you need to know about form validation.attribute to turn off the browser's automatic validation; this lets our script take control over validation.However, this doesn't disable support for the constraint validation API nor the application of the CSS pseudo-class or other As you can see, the HTML is almost the same; we just removed the HTML validation features.More and more browsers now support the constraint validation API, and it's becoming reliable.