html中给radio赋值

<form name="form1" >
    <input type="radio" name="sex" value="1">男　 <input type="radio" name="sex" value="0">女　
</form>
<script>
    window.onload=function(){
        var sex=1
        var ridaolen=document.form1.sex.length;
        for(var i=0;i<ridaolen;i++){
            if(sex==document.form1.sex[i].value){
                document.form1.sex[i].checked=true
            }
        }
       
    }
</script>