How to use regular expressions to limit the input of text boxes_html/css_WEB-ITnose

What should I do if I want to restrict the input of specific numbers, such as only 0 and 1?
How to restrict it

Reply to discussion (solution)

<input type="text" name="text" id="demo" /><script type="text/javascript">document.getElementById('demo').onchange = function() {	if (!/^[01]+$/.test(this.value)) {		alert('非法字符');		this.value = '';	}}