JSFiddle - React, Tailwind, and code Playground

by Prasad Gavande

HTML

<input type="text" id="txtGradeNumber" />
<input type="button" id="btn" />

JavaScript

var regularFieldValidation = function (elementValue, elementId, regExp) {
        alert(regExp);
        if (!regExp.test(elementValue)) {
            alert("in if of reg expression test");
            $(elementId).css("border-color", "red");
            return false;
        }
    };

    $(document).ready(function () {
        var gradeNumber = $("#txtGradeNumber").val();
        $("#btn").on("click", function () {
            var a = /^\d*$/;
            var checkRegExpValidation = regularFieldValidation(gradeNumber, "#txtGradeNumber", a);
            alert("return value" + checkRegExpValidation);
            if (!checkRegExpValidation) {
                alert("not");

            } else {
                alert("yes");
            }

        });
    });