<div id="ele">welcome to www.49028c.com</div>

<script type="text/javascript">
  document.getElementById('ele').innerHTML= 'welcome to my blog';
</script>

 <div id="ele">welcome to www.49028c.com</div>
<script type="text/javascript">
  document.getElementById('ele').innerHTML='welcome to my blog';
</script>

<script>
$(document).ready(function(){
   document.getElementById('ele').innerHTML= 'welcome to my blog';
});
</script>
//當然,既然用到了jQuery,更簡單的寫法是：
<script>
$(document).ready(function(){
   $('#ele').html('welcome to my blog'); //這里也可用.text()方法
});
</script>