方法1

<script type="text/javascript">   

function password() {   

var testV = 1;   

var pass1 = prompt('请输入密码','');   

while (testV < 3) {   

if (!pass1)   

history.go(-1);   

if (pass1 == "123") {//初始密码123   

alert('密码正确');   

break;   

}   

testV+=1;   

var pass1 =   

prompt('密码错误!请重新输入:');   

}   

if (pass1!="password" & testV ==3)   

history.go(-1);   

return " ";   

}   

document.write(password());   

</script>  

<!--下面添加你要显示的内容或者代码-->

方法2

<script type="text/javascript">   

loopy()   

function loopy() {   

var sWord =""  

while (sWord != "123") {//设置密码

sWord = prompt("输入正确密码才能登陆!")   

}   

alert("欢迎访问")   

}   

</script> 

<!--下面添加你要显示的内容或者代码-->

方法3

<script type="text/javascript">   

function password() {   

var testV = 1;   

var pass1 = prompt('请输入密码:','');   

while (testV < 3) {   

if (!pass1)    

history.go(-1);   

if (pass1 == "123") {//设置密码

alert('口令正确，进行跳转');   

window.location.href="http://test.junyao2018.cn/";//添加你要跳转的页面

break;   

}    

testV+=1;   

var pass1 =    

prompt('密码错误','');   

}   

if (pass1!="password" & testV ==3)    

history.go(-1);   

return " ";   

}    

document.write(password());   

</script>