HTML/JSP Disabled Form Field's Strange Behavior

Disabled Form Fields of HTML Will Not Get the Values (Null) After Submitting the Form

Using the code below for the input form fields in HTML will generate the disabled field. The disabled field is the one which is not editable, not focusable, won’t get tab navigation, and can’t select the field. We can apply this attribute on all input fields, buttons, select box, etc. 

Please see the code below:

<input type=”text” name=”accountNumber” value=”123455” disabled=”disabled”   />

This will generate the disabled text field where we are unable to edit and select the field.

Characteristics of Disabled Form Fields

1. Disabled form field cannot be focusable, i.e., you cannot focus the field. 
2. Disabled fields are non-editable.
3. Disabled fields will not be submitted when submission of the form happens or when we click on the Submit button.
4. Disabled fields will give null values after submitting the form where you are getting the values (it may be struts action class in case of struts or servlet class in case of servlets).
5. We can modify the values of disabled fields only through JavaScript at the client side.

How to Get Disabled Behavior for Any of the Input Fields and Get the Non-null Values After Form Submission

1. Make the field readOnly instead of disabled  by putting the attribute as readonly=”readonly” for html fields and readOnly=”true” for struts JSP fields.
2. Prepare the CSS with the color of disabled fields (i.e. gray color), and apply the CSS to the fields which you made as readonly. Now the field is uneditable because of the readonly attribute and looks like the disabled field because of the CSS applied.

Characteristics of readonly Fields

1. Fields are not editable through the screen.
2. Fields can be modified through JavaScript code at client side.
3. Fields can be Focusable.
4. Fields can be selectable.
5. Tab navigation is possible on the fields.
6. Values can be submitted after form submission.
7. There are no null values after form submission whenever the field contains values while submitting.

This will solve the issue with disabled fields used in the view layer for a specific purpose and will help to get the disabled behavior.

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