直接给出代码了：
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> <HTML> <HEAD> <TITLE> New Document </TITLE> <META CONTENT="EditPlus"> <META CONTENT=""> <META CONTENT=""> <META CONTENT=""> </HEAD> <BODY> <input onkeyup='check(this)'/> </BODY> <script> function check(obj){ var sreg = /^-+.*/g; var zero = /^0[1-9]+\.*\d*/g; var val = obj.value; var plus = ''; if(sreg.test(val)){ val = val.replace(/-+/g,''); plus = '-'; } val = val.replace(/\s+/g,''); if(/^\.+.*$/.test(val)){ val = ''; } val = val.replace(/[^\d\.]/,''); val = val.replace(/(^\d+\.{1})(\d*).*/g,'$1$2'); val = val.replace(/(^\d+\.\d{3})\d*/g,'$1'); val = val.replace(/^[0]*(0{1})([1-9]*)(.*)/g,'$1$2$3'); if(zero.test(val)){ val = val.replace(/0([1-9]+)(.*)$/,'$1$2'); } obj.value = plus+val; } </script> </HTML>
脚本之家写的一个替换 非数字与中英文逗号的函数，需要的朋友可以参考一下
function renumdou(str){ var regexp = /[^\d，,]]*/g; newstr=str.replace(regexp,""); return newstr }