mobilenumber.html

<html>
    <head>
        <title>mobile number validiation</title>
        <script type="text/javascript">
        /*
        \d=match any digit(equal to [0-9])
        \w=match any word character(a-z,A-Z,0-9 & _)
        \s=match whitespace character(eg-space & tab)
        \t=match a tab only
        */
        function validiate()
        {
            var text=document.getElementById("text1").value;
            var regx=/^[7-9][0-9]{9}$/;
            if(regx.test(text))
            {
                document.getElementById("lbtext").innerHTML="valid";
                document.getElementById("lbtext").style.visibility="visible";
                document.getElementById("lbtext").style.color="green";
            }
            else{
                document.getElementById("lbtext").innerHTML="invalid";
                document.getElementById("lbtext").style.visibility="visible";
                document.getElementById("lbtext").style.color="red";
            }
        }
        </script>
        </head>
        <body>
            <form>
             <input id="text1" placeholder="cellphone" type="text"/><br><br>
             <label id="lbtext" style="color : red;visibility:hidden">Invalid</label>
             <br>
             <button onclick="validiate()" type="button">submit</button>
            </form>
        </body>
</html>