In addition, each of the fields should have a unique name.
Use the following table to assign names to all of your form elements.
You need a custom function that you can later connect to the form.
For more information about creating a function, see JScript Functions.
You may assign any name you want that is composed of alphanumeric characters (without spaces), but to make writing the code easiest, you should provide a useful, friendly name for each of the fields.
In this table, Element refers to the name of the HTML element for the form field, Type refers to the value of the type attribute for the form field, and Label refers to the text to the left of the form field. Form code updated with name attribute values Now that you have assigned names for the form and form fields, you are ready to start writing the script that handles the validation for the fields. If you are typing the Java Script code in this article manually and receive errors, you should check that all casing is the same as shown in this article.
Otherwise, you may want to review JScript Run-Time and Syntax errors.
The validation script in this article returns a Boolean value that specifies whether the data contained in the form is valid. Variables are not required, but they make accessing each field easier.
To create your own custom function, insert a SCRIPT element into the HEAD section of your form page; within the SCRIPT element, use the function statement to insert a function named Validate Contact Form. This code should look something like the following code sample. Starting script function To access the form fields within the code, you should create variables. For example, without a variable, you would have to type document. Name every time you needed to access the Name field.