<ul id="a">
<li><span id="s">这里需要编辑</span><input type="text" id="t" style="display:none" onblur="ee()"/></li>
<li><a href="javascript:void(0);" class="b" onclick="se()">编辑</a></li>
</ul>

<script type="text/javascript">
var ss = document.getElementById("s");
var tt = document.getElementById("t");

se = function(){
    tt.value = ss.innerHTML;
    ss.style.display = "none";
    tt.style.display = "block";
}

ee = function(){
    ss.innerHTML = tt.value;
    tt.style.display = "none";
    ss.style.display = "block";

}

</script>