自己写的js加密

<script>
function changeText(obj,str)
{? var len=str.length;
?? var rs="";
?? for(var i=0;i<len;i++){
????????? var k=str.substring(i,i+1);
????????? rs+= (i==0?"":i)+str.charCodeAt(i);
????

?? }
? obj.value =rs;
}
function change(obj)
{?
? obj.value ="********************";
? document.getElementById("uname").select();
}
</script>
name:<input id="uname" onblur="changeText(this,this.value);" onfocus="change(this)"/>