Custom Validation Messages for HTML Forms
In an HTML form, when aREQUIRED field is left blank, a default message usually appears saying "Please fill out this field." This can be customized to provide a more specific and user-friendly error message.
Changing the Default Error Message
To change the default error message, use thesetCustomValidity()method. For example, to set the error message for an input field with the id "username" to "This field cannot be left blank," add the following code:
<input type="text">
Hiding the Error Message
After the user inputs data into the field, the error message should be hidden. This can be done by setting the error message to "" using the oninput event handler:
oninput="this.setCustomValidity('')"
Note: The "this" keyword is not required for inline event handlers but can be used for consistency.
Example
The following code demonstrates the use ofsetCustomValidity()to provide a custom error message and hide it when the user inputs new data:
<form>
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