JS中将多个逗号替换为一个逗号的实现代码

<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; 
}