Here is some code to display a custom error message:
<input type="text" id="username" required placeholder="Enter Name"
oninvalid="ths.setCustomValidity('Enter User Name Here')"
oninput="setCustomValidity('')"/>
This part is important because it hides the error message when the user inputs new data:
oninput="setCustomValidity('')"
Note: the this
keyword is not required for inline event handlers, but you may want to use it anyway for consistency.