如何使用 javascript 从一个页面到另一个页面？

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最佳答案

To simply redirect a browser using javascript:

window.location.href = "http://example.com/new_url";

To redirect AND submit a form (i.e. login details), requires no javascript:

<form action="/new_url" method="POST">
<input name="username">
<input type="password" name="password">
<button type="submit">Submit</button>
</form>

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Verifying that a user is an admin in javascript leads to trouble because javascript code is visible to anyone. The server is the one who should tell the difference between an admin and a regular user AFTER the login process and then generate the new page accordingly.

Maybe that's not what you are trying to do so to answer your question:

window.location.href="<the page you are going to>";

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You cannot sanely depend on client side JavaScript to determine if user credentials are correct. The browser (and all code that executes that) is under the control of the user, not you, so it is not trustworthy.

The username and password need to be entered using a form. The OK button will be a submit button. The action attribute must point to a URL which will be handled by a program that checks the credentials.

This program could be written in JavaScript, but how you go about that would depend on which server side JavaScript engine you were using. Note that SSJS is not a mainstream technology so if you really want to use it, you would have to use specialised hosting or admin your own server.

(Half a decade later and SSJS is much more common thanks to Node.js, it is still fairly specialised though).

If you want to redirect afterwards, then the program needs to emit an HTTP Location header.

Note that you need to check the credentials are OK (usually by storing a token, which isn't the actual password, in a cookie) before outputting any private page. Otherwise anyone could get to the private pages by knowing the URL (and thus bypassing the login system).

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The correct solution that i get is

<html>
<head>
<script type="text/javascript" language="JavaScript">
function clickedButton()
{


window.location = 'new url'


}
</script>
</head>


<form name="login_form" method="post">
..................
<input type="button" value="Login" onClick="clickedButton()"/>
</form>
</html>

Here the new url is given inside the single quote.

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Try this,

window.location.href="sample.html";

Here sample.html is a next page. It will go to the next page.

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Easier method is window.location.href = "http://example.com/new_url";

But what if you want to check if username and password whether empty or not using JavaScript and send it to the php to check whether user in the database. You can do this easily following this code.

html form -

<form name="myForm" onsubmit="return validateForm()" method="POST" action="login.php" >
<input type="text" name="username" id="username" />
<input type="password" name="password" id="password" />
<input type="submit" name="submitBt"value="LogIn" />
</form>

javascript validation-

function validateForm(){
var uname = document.forms["myForm"]["username"].value;
var pass = document.forms["myForm"]["password"].value;


if((!isEmpty(uname, "Log In")) && (!isEmpty(pass, "Password"))){


return true;
}else{
return false;
}
}


function isEmpty(elemValue, field){
if((elemValue == "") || (elemValue == null)){
alert("you can not have "+field+" field empty");
return true;
}else{
return false;
}
}

check if user in the database using php

<?php
$con = mysqli_connect("localhost","root","1234","users");


if(mysqli_connect_errno()){
echo "Couldn't connect ".mysqli_connect_error();
}else{
//echo "connection successful <br />";
}


$uname_tb = $_POST['username'];
$pass_tb = $_POST['password'];


$query ="SELECT * FROM user";
$result = mysqli_query($con,$query);


while($row = mysqli_fetch_array($result)){
if(($row['username'] == $uname_tb) && ($row['password'] == $pass_tb)){
echo "Login Successful";
header('Location: dashbord.php');
exit();
}else{
echo "You are not in our database".mysqli_connect_error();
}
}
mysqli_close($con);
?>

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For MVC developers, to redirect a browser using javascript:

window.location.href = "@Url.Action("Action", "Controller")";

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There are a few more ways to redirect:

location.replace("http://example.com");
location.href = "http://example.com"
window.location = "http://example.com"
window.location.href = "http://example.com"