js 中将多个逗号替换为一个逗号的代码

<script language="javascript"> 
var str="asdfk,asdf34,,,,,,5345,,,,";
str=str.replace(new RegExp(',+',"gm"),',');
alert(str);
</script>

function dostr(str){
str=trim(str);
var strarry=unique(str.split(","));
str=strarry.join(",");
str=str.replace(/，/ig,",");
str=str.replace(/[^0-9,]*/ig,"");
str=str.replace(new RegExp(',+',"gm"),',');
if (str.substr(0,1)==',') str=str.substr(1);
var reg=/,$/gi;
str=str.replace(reg,"");
return str;
}