Need help in javascript

To check the focus existance of the textbox is not straight forward and you could do this..
var txtFocus = null;

  window.onload = function() {
    var inputs = document.getElementsByTagName('INPUT');

    for(var i = 0; i < inputs.length; i++) {
      var elem = inputs[i];

      if(elem.type == 'text') {
        elem.onfocus = function() {
          txtFocus = this;
        }
        elem.onblur = function() {
          txtFocus = null;
        }
      }
    }
  }

Now you can check the variable "txtFocus" whenever you need to see what textbox has focus, just like this...

  if(txtFocus)
    alert(txtFocus.id + ': ' + txtFocus.value);
  else
    alert('No textbox currently has focus!');

Depending on this, you could proceed further

Start from here: click click and maybe click