If correct, the application allows the data to be submitted to the server and (usually) saved in a database; if not, it gives you error messages to explain what you've done wrong (provided you've done it right).
We also want to help our users to fill out our forms correctly and not get frustrated when trying to use our apps.
It means the application will be more responsive because the load on the server is reduced.
You can find many solutions on the web but I found that the most of these solutions are to validate the phone number from one text box. The following image shows phone number input fields (eg: 1) Basically, there are two to validate the phone numbers. The second is to have the phone number not mandatory but if the user enters in any one of the three textbox fields, then the validation takes place.
Method 2 Validation Conditions Each textbox field should pass the following validation.
Before we start, just note Eg: document.form1(is just an object), document.form1value (has value of that area object) Method 1 - (Phone Number is a mandatory field) To validate this condition is very simple.