Javascript_input、textArea实时显示剩余可输入的字数

 <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;}