var s = document.getElementById('input');
                  var b = document.getElementById('btn');

                    b.disabled = true;
                    s.style.color = '#aaa';
                    s.value = '< Suchbegriff >';
                    s.blur();

                  s.onfocus = function() {
                    if(s.value == '< Suchbegriff >') {
                      s.value = '';
                      s.style.color = 'black';
                    } else
		      s.style.color = 'black';
                  }
                  s.onblur = function() {
                    if(s.value == '') {
                       s.style.color = '#aaa';
                       window.setTimeout(function() {
                         s.value = '< Suchbegriff >';
                       }, 1);
                    } else {
		      s.style.color = 'black';
		    }
                  }
                  function reqUpdate() {
                    var s = document.getElementById('input');
                    var b = document.getElementById('btn');
                    var str = s.value;
                    if(str == "< Suchbegriff >") {
                      str = "";
                    } else {
		      s.style.color = 'black';
		    }
                    str = str.replace(/ /g, "");
                    if(str.length == 0) {
                      b.disabled = true;
                    } else {
                      b.disabled = false;
                    }
                  }
                  function sub() {
                    reqUpdate();
                    if(document.getElementById('btn').disabled)
                      return false;
                    return true;
                  }
                  arr = ["keyup", "mouseup", "click", "keypress", "change"];
                  for(var i = 0; i < arr.length; i++) {
                    document["on" + arr[i]] = reqUpdate;
                    window["on" + arr[i]] = reqUpdate;
                  }
                  reqUpdate();
                  document.getElementById('frm').onsubmit = sub;