js text box for real-time calculation of word count reminder_form special effects

I thought for a while that it should be implemented in JavaScript, and I made it today. The principle is very simple: get the length of the characters in the current text box based on the onkeyup event triggered by the text box, and then subtract the current number of characters from the maximum number of characters allowed in the text box, and display it with the label control.
Rendering:

Demo code:

<title>enter</title> <center> <div style="text-align:left;"> <h3> </h3>Nickname:<input type="text" id="mytext1" maxlength="15" onkeyup="keypress1()"> <font color="gray"> <label id="name"></label>You can also enter 15 characters</font><h3> </h3>Comment content:<br><textarea id="myarea" style="height:100px;width:200px;overflow-x:hidden;overflow-y:hidden" onkeyup="keypress2()" onblur="keypress2()"> <font color="gray"> <label id="pinglun"></label>You can also enter 300 characters</font><div> <br><input onclick="runEx('runcode66343')" type="button" value="运行代码"><input onclick="doCopy('runcode66343')" type="button" value="复制代码"> <input onclick="doSave(runcode66343)" type="button" value="保存代码"> <a href="http://www.jb51.net/article/23421.htm" title="查看具体详情" target="_blank">[Ctrl A select all Note: </a>If you need to introduce external Js, you need to refresh to execute </div>]<script language="javascript"> function keypress1() //text输入长度处理 { var text1=document.getElementById("mytext1").value; var len=15-text1.length; var show="你还可以输入"+len+"个字"; document.getElementById("name").innerText=show; } function keypress2() //textarea输入长度处理 { var text1=document.getElementById("myarea").value; var len;//记录剩余字符串的长度 if(text1.length>=300)//textarea控件不能用maxlength属性，就通过这样显示输入字符数了 { document.getElementById("myarea").value=text1.substr(0,300); len=0; } else { len=300-text1.length; } var show="你还可以输入"+len+"个字"; document.getElementById("pinglun").innerText=show; } </script>