<body>
<input type="text" name="" id="txt">
<input type="button" name="" value="加密" id="btn">
<input type="text" name="" id="mw">
</body>
<script>
var txt=document.getElementById("txt")
var btn=document.getElementById("btn")
var mw=document.getElementById("mw")
btn.onclick=function(){
var sz = txt.value;
jm(sz);
}
function jm(Text){
var temp,tem;
var qian=(parseInt(Text/1000)+5)%10;
console.log(qian)
var bai=(parseInt(Text%1000/100)+5)%10;
console.log(bai)
var shi=(parseInt(Text%100/10)+5)%10;
console.log(shi)
var ge =(parseInt(Text%10)+5)%10;
console.log(ge)
temp=qian;
qian=ge
ge=temp;
tem=shi;
shi=bai;
bai=tem;
// console.log(bai)
mw.value=qian*1000+bai*100+shi*10+ge
}
</script>
原文：https://www.cnblogs.com/cupid10/p/12789562.html