修改html中button显示的文字

1. <input type="button">  实现密码输入框的可见和隐藏

直接修改value属性即可

<script type="text/javascript">
function getPasswd(){
    var passwd = document.getElementById("pwdID");
    var pwdBtn = document.getElementById("pwdBtnID");
    if(passwd.type=="password")    {
        passwd.type="text";
        pwdBtn.value="隐藏";
    }
    else{
        passwd.type="password";
        pwdBtn.value="显示";
    }
}
</script>

密码：<input id="pwdID" type="password">
<input id="pwdBtnID" type="button" onclick="getPasswd()" value="显示">

2. <button> 实现视频的播放和暂停

修改button的innerHTML

<script type="text/javascript">
function playVideo(){
    var videoDiv = document.getElementById("videoId");
    var videoBtn = document.getElementById("videoBtn");
    if(videoDiv.paused){
        videoDiv.play();
        videoBtn.innerHTML = "暂停";
    }
    else{
        videoDiv.pause();
        videoBtn.innerHTML="播放";
    }
}
</script>

<button id="videoBtn" type="button" onclick="playVideo()">播放</button>

 3. innerHTML、innerText、outerHTML、outerText

innerHTML是符合W3C标准的属性，其它属性不推荐使用