直接给出代码了：
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML>
<HEAD>
<TITLE> New Document </TITLE>
<META NAME="Generator" CONTENT="EditPlus">
<META NAME="Author" CONTENT="">
<META NAME="Keywords" CONTENT="">
<META NAME="Description" 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
}
