<!DOCTYPE html>
<html>

  <head>

    <script type="text/javascript">
      function valid() {
        var flag = 0;
        var name = document.udetail.uname.value;
        var age = document.udetail.uage.value;
        var eid = document.udetail.ueid.value;
        var atrate = eid.indexOf("@");
        var dot = eid.lastIndexOf(".");
        var country = document.getElementById('ucountry').value;
        var query = document.udetail.uquery.value;
  
  
        if (name == "") {
          document.getElementById('uname').innerHTML = "Name is mandatory.";
          flag = 0;
        } else {
          document.getElementById('uname').innerHTML = "";
          flag++;
        }
  
        if (age == "") {
          document.getElementById('uage').innerHTML = "Age is mandatory.";
          flag = 0;
        } else {
          document.getElementById('uage').innerHTML = "";
          flag++;
        }
  
        if (eid == "") {
          document.getElementById('ueid').innerHTML = "Email Id is mandatory.";
          flag = 0;
        } else if (atrate < 1 || dot < atrate + 2 || dot + 2 >= eid.length)
          document.getElementById('ueid').innerHTML = "Invalid Email Id.";
        else {
          document.getElementById('ueid').innerHTML = "";
          flag++;
        }
  
        if (country == '') {
          document.getElementById('fucountry').innerHTML = "Country is mandatory.";
          flag = 0;
        } else {
          document.getElementById('fucountry').innerHTML = "";
          flag++;
        }
  
        if (query == '') {
          document.getElementById('fquery').innerHTML = "Please enter a query."
          flag = 0;
        } else {
          document.getElementById('fquery').innerHTML = "";
          flag++;
        }
  
        if (flag == 5) {
          alert("Thank You! Your query will be answered soon.")
        }
      }
    </script>
  </head>

  <body>
    <form name="udetail">
      <table align="center">
        <tr>
          <td>
            Name
          </td>
          <td>
            -
            <input type="text" name="uname" placeholder="Your Name">
          </td>
          <td>
            <font color="red" id="uname"></font>
          </td>
        </tr>
        <tr>
          <td>
            Age
          </td>
          <td>
            -
            <input type="text" name="uage" placeholder="Your Age">
          </td>
          <td>
            <font color="red" id="uage"></font>
          </td>
        </tr>
        <tr>
          <td>
            Email Id
          </td>
          <td>
            -
            <input type="text" name="ueid" placeholder="Your Awesome Email">
          </td>
          <td>
            <font color="red" id="ueid"></font>
          </td>
        </tr>
        <tr>
          <td>
            Country
          </td>
          <td>
            -
            <select id="ucountry">
              <option selected> </option>
              <option>India</option>
              <option>U.S.</option>
              <option>Russia</option>
              <option>China</option>
              <option>Other</option>
            </select>
          </td>
          <td>
            <font color="red" id="fucountry"></font>
          </td>
        </tr>
        <tr>
          <td>
            Query
          </td>
          <td>
            -
            <textarea cols="22" rows="5" name="uquery" placeholder="Enter your questions, feedback or query here."></textarea>
          </td>
          <td>
            <font color="red" id="fquery"></font>
          </td>
        </tr>
      </table>
      <p align="center">
        <input type="button" value="Submit" onclick="valid()">
      </p>
    </form>

  </body>

</html>