JavaScript 实现数字千分位格式化的简单方法

<script language="javascript" type="text/javascript">
function comdify(n){
　　var re=/\d{1,3}(?=(\d{3})+$)/g;
　　var n1=n.replace(/^(\d+)((\.\d+)?)$/,function(s,s1,s2){return s1.replace(re,"$&,")+s2;});
　　return n1;
}

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<input type="text" value="1212133345.78" onblur="this.value=comdify(this.value)">