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    <title>Document</title>
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   <!-- <input type="textbox" id="T1" placeholder="Press any key" onkeyup="displaytext()">
    <script>
        function displaytext()
        {
            document.getElementById("T1").value="Hello World!!";
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    <H1 id="H1"></H1>
    <input type="textbox" id="T1" placeholder="Enter Customer's Name" onkeypress="return validate_text(event)">

    <script>
        function validate_text(event)
        {
            document.getElementById("H1").innerHTML=event.keyCode;
            if(event.keyCode>=48 && event.keyCode<=57)
            {
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