How to change the input value of an inline-blocked blank field to single-byte alphanumeric characters

Is there any CSS setting that allows only single-byte alphanumeric characters to be entered into a blank field that has been set to inline-block?

Currently, I have the following settings in HTML and CSS.
HTML

<div id=”CodeText” contenteditable=”true” class=”ui-state-highlight”>1244</div>

CSS

#CodeText {
display: inline-block;
}

With the above configuration, if a value other than a single-byte alphanumeric value is entered for CodeText, is there any way to suppress it?