How to Remove/Find Word in TextBox Through java Script

How to Remove/Find Word in TextBox Through java Script

1. Java script code

  function ButtonDisplay_onclick() {

            var i;
            var words = new Array();
            words[0] = "Rakesh";
            words[1] = "Rahul";
            words[2] = "Riyan";
            var s = document.getElementById("DisplayTxt").value;
            var s2 = document.getElementById("div_ID ").value; 
            for (i = 0; i < words.length; i++) {
                if (s.match(words[i]) == words[i]) {
                    document.getElementById("DisplayTxt").focus();
                    document.getElementById("DisplayTxt").value = "";
                }
           }
}

2. HTML Code

<div id="div_ID">

        <input id="ButtonDisplay" type="button" value="Click On"onclick="return ButtonDisplay_onclick()" />        <input type="text" id="DisplayTxt" />
   </div>