Knowledge Walls
John Peter
Pune, Maharashtra, India
Examples
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How to validate textbox using javascript with Example
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Example
<html>
    <head>
        <title>getElementsByName example</title>
        <script type="text/javascript">
            function validate(){
                if (document.getElementById("txt_username").value == ""){
                   alert("Enter the username");
                   document.getElementById("txt_username").focus();
                }
                else {
                   alert("Everything Okay");
                }
            }
        </script>
    </head>
    <body>
        Username: <input type="text" id="txt_username" />
        <button onclick="javascript:validate();">Validate</button>
    </body>
</html>
Demo & Output 
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