复制代码代码如下：
<script>
函数doclick1（）{
var txtn = document.getElementsbytagname（“ input”）;
for（i = 0; i <txtn.length; i ++）{
if（txtn [i] .type =“ text”）{
txtn [i] .readonly = false;
}
}
}
</script>
<输入type =“ text” id =“ contactus1” readonly>
<输入type =“ text” id =“ contactus2” readonly>
<输入type =“ text” id =“ contactus3” readonly>
<input type =“ button” name =“ button4” value =“修改” onclick =“ doclick1（）;” />