<input type="text" name="textfield" id="text_input" /><div>您输入的值为：<span id="test">还未输入</span></div>

<script type="text/javascript">function immediately(){  var element = document.getElementById("text_input");  if("\v"=="v") {  //IE 6 7 8    element.onpropertychange = webChange;  }else{    element.addEventListener("input",webChange,false);  }  function webChange(){    if(element.value){document.getElementById("test").innerHTML = element.value};  }}immediately();</script>