<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <title>计算字符-Demo1</title> </head> <body> <div id="tips">最多10个字</div> <input type="text" value="" onkeyup="test(this)" /> <script type="text/javascript"> var num=15; function len(x){ var text=x; return text.replace(/[^x00-xff]/g,"**").length; //汉字替换为2字符 } function test(obj){ var tips = document.getElementById("tips"); var str = obj.value; var n=Math.ceil(len(str)/2); if((num-n)>0){ tips.innerHTML="你还可以输入"+(num-n)+"个字"; }else{ thips.innerHTML="你还可以输入"+(n-num)+"个字"; } } </script> </body> </html>
写法2：
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <title>计算字符-Demo1</title> </head> <body> <div id="tips">最多10个字</div> <input type="text" value="" onkeyup="test(this)" /> <script type="text/javascript"> var num=15; String.prototype.len=function(){ return this.replace(/[^x00-xff]/g,"**").length; //汉字替换为2字符 } function test(obj){ var tips = document.getElementById("tips"); var str = obj.value; var n=Math.ceil(str.len()/2); if((num-n)>0){ tips.innerHTML="你还可以输入"+(num-n)+"个字"; }else{ thips.innerHTML="你还可以输入"+(n-num)+"个字"; } } </script> </body> </html>