<h2>实时显示剩余可输入的字数（字母，数字，中文都算一个字）</h2>
    <h>昵称:</h>
    <input type="text" id="myText" maxlength="15" onKeyUp="keypress1()"/>
    <label id="name">15</label><span>/</span><label>15</label>
    <br>
    <h>评论内容:</h><br>
    <textarea id="myArea" style="width: 100px;" cols="10"   rows="3" onKeyUp="keypress2()" onblur="keypress2()"></textarea>
    <label id="pinglun">30</label><span>/</span><label>30</label>

function keypress1(){
    var text1=document.getElementById("myText").value;
    var maxLen=document.getElementById("myText").maxLength;
    var len=maxLen-text1.length;
    document.getElementById("name").innerText=len;}
function keypress2(){
    var text1=document.getElementById("myArea").value;
    var maxLen=document.getElementById("myArea").cols*document.getElementById("myArea").rows;
    var len;//记录剩余字符串的长度
    if(text1.length>=maxLen)
    {
        document.getElementById("myArea").value=text1.substr(0,maxLen);//只显示起始位-末尾；substr（起始位，末尾)
        len=0;
    }else{
        len=maxLen-text1.length;
    }
    document.getElementById("pinglun").innerText=len;}