JSFiddle - React, Tailwind, and code Playground

HTML

<p><input type="text" class="decimal" value="0" /></p>
<p><input type="text" class="decimal" value="-1" /></p>
<p><input type="text" class="decimal" value="0.5" /></p>
<p><input type="text" class="decimal" value="99.9" /></p>
<p><input type="text" class="decimal" value="100" /></p>
<p><input type="text" class="decimal" value="10Hi" /></p>

<p>
    <input type="button" id="validate" value="Validate"/>
</p>

JavaScript

$("#validate").click(function(){
    $(".decimal").each(function(){
        var v = $(this).val();
        
        //pattern: integer or decimal
        var valid = /^\d+$/.test(v) || /^\d+\.\d+$/.test(v);
        
        $(this).parent().find("i").remove();
        $(this).parent().append("<i>" + (valid ? "valid" : "invalid")  + "</i>");
    });
});
$("#validate").click();