JavaScript - Required Field Validator for TextBox on Submit

In this code snippet we will check how to validate textboxes on submit, JavaScript function for Required field validator for Textboxes on Submit.

Required Field Validator on Submit

JavaScript function:

<style type="text/css">
    .reqError {
        color: #ff0000; /*Red Color*/
        font-weight: bold;
    }
</style>
<script type="text/javascript">
    //function to check validation (Required field)
    function checkReqFields() {
        var returnValue;
        var name = document.getElementById("txtName").value;
        var address = document.getElementById("txtAddress").value;

        returnValue = true;
        if (name.trim() == "") {
            document.getElementById("reqTxtName").innerHTML = "* Name is required.";
            returnValue = false;
        }
        if (address.trim() == "") {
            document.getElementById("reqTxtAddress").innerHTML = "* Address is required.";
            returnValue = false;
        }
        return returnValue;
    }
</script>

JavaScript and HTML Code to Required Field Validator for TextBox on Submit

<!--JavaScript - Required Field Validator for TextBox on Submit.-->
<html>
    <head>
        <title>JavaScript - Required Field Validator for TextBox on Submit</title>
        <style type="text/css">
            .reqError {
                color: #ff0000; /*Red Color*/
                font-weight: bold;
            }
        </style>
        <script type="text/javascript">
            //function to check validation (Required field)
            function checkReqFields() {
                var returnValue;
                var name = document.getElementById("txtName").value;
                var address = document.getElementById("txtAddress").value;

                returnValue = true;
                if (name.trim() == "") {
                    document.getElementById("reqTxtName").innerHTML = "* Name is required.";
                    returnValue = false;
                }
                if (address.trim() == "") {
                    document.getElementById("reqTxtAddress").innerHTML = "* Address is required.";
                    returnValue = false;
                }
                return returnValue;
            }
        </script>
    </head>
    <body>
        <h1>JavaScript - Required Field Validator for TextBox on Submit</h1>
        <form onsubmit="return checkReqFields()">
            <b>Enter Name: </b><br />
            <input type="text" id="txtName" />
            <span id="reqTxtName" class="reqError"></span><br />
            <br />

            <b>Enter Address: </b><br />
            <input type="text" id="txtAddress" />
            <span id="reqTxtAddress" class="reqError"></span><br />

            <p><input type="submit" value="Submit" /></p>
        </form>
    </body>
</html>