JSFiddle - React, Tailwind, and code Playground
HTML
<TITLE>onBlur Event Handler</TITLE>
<SCRIPT>
function validate(value) {
if (value < 0) alert("Please input a value that is greater or equal to 0");
}
</SCRIPT>
<BODY>
<H3> onBlur Event Handler</H3>
Try inputting a value less than zero:<BR>
<FORM>
<INPUT TYPE="text" onBlur="validate(this.value)">
</FORM>
</BODY>