<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8"> <title>显示输入剩余字数</title> <script> var maxstrlen=160; function Q(s){return document.getElementById(s);} function checkWord(c){ len=maxstrlen; var str = c.value; myLen=getStrleng(str); var wck=Q("wordCheck"); if(myLen>len*2){ c.value=str.substring(0,i+1); } else{ wck.innerHTML = Math.floor((len*2-myLen)/2); } } function getStrleng(str){ myLen =0; i=0; for(;(i<str.length)&&(myLen<=maxstrlen*2);i++){ if(str.charCodeAt(i)>0&&str.charCodeAt(i)<128) myLen++; else myLen+=2; } return myLen; } </script> </head> <body> <div style="font-size:16px"> 控制输入框字符输入，计算输入字符总数,显示剩余字数;<br> 一个英文字符算一个字符，一个中文字符算两个字符计算。 </div> <div> <textarea onKeyUp="javascript:checkWord(this);" onMouseDown="javascript:checkWord(this);" name="content" style="overflow-y:scroll"></textarea> </div> <DIV> 还可以输入<span style="font-family: Georgia; font-size: 26px;" id="wordCheck">160</span>个字符 </div> </body> </html>