我的代码不起作用，怎么了？

Question

I'm new to JavaScript, but I followed a really good tutorial, and I'm making a sign in pop-up form, but it doesn't work... The idea is that you have one username, and one password, if both are correct, you will redirect to a page. I lost the HTML code for the form, but with an input field, the id has to be uName, and with the password field pWord. Here's my JavaScript code:

function myFunction(){

    var uName = document.getElementById("uName").value;
    var pWord = document.getElementById("pWord");


}


// This line controls the uName and pWord.

if(uName = "Admin",pWord = "Admin"){

// This line creates a pop-up with the name.

alert("Welcome " + uName);

// Need a line to redirect to a new page

// Need a line with the else statement

// Need a line to say if something if not all fields are filled


}

The username has to be Admin and the password Admin. If you don't enter the right combination, you have to get a message like: "Incorrect combination.".

Answer 1

This is assignment with = operator :

if (uName = "Admin",pWord = "Admin") {

While you need comparison == or === :

if (uName == "Admin" && pWord == "Admin") {

Also usage of the comma , operator is not correct (well it is correct, but not in this place). You need logical AND && .

Assignment inside of if check makes truthy expression ("Admin" string is truthy), making code always enter if-block.

Answer 2

There's a couple of issues:

1. You're not getting the value of the password field, but the object
2. You're not validating the credentials inside the function
3. You are assigning "Admin" to uName and pWord with a single =
4. You need to use && to match both tests of your if statement

As a side note: You should never validate a login with the username and password hardcoded like this, it is always avaiable to the user, all you would need to do is right click in browser and view source to see the username and password - this login script is fine for learning how javascript works, but don't implement a login like this in the real world unless it is purely a crawler type deterrent

= sets a value, == matches the value, === matches the value and type (string, object, int)

function myFunction(){

    var uName = document.getElementById("uName").value;
    var pWord = document.getElementById("pWord").value;

    // This line controls the uName and pWord.

    if(uName == "Admin" && pWord == "Admin"){

        // This line creates a pop-up with the name.

        alert("Welcome " + uName);

        // Need a line to redirect to a new page

        // Need a line with the else statement

        // Need a line to say if something if not all fields are filled
    }

}

To combat your comments

// Need a line to redirect to a new page
window.location.href="/pagetoredirectto.html";

and

// Need a line with the else statement
if(uName == "Admin" && pWord == "Admin"){

    alert("Welcome " + uName);

} else {

    alert( "User and Pass do not match" );

}

and this should go just after you get the values.. so the full code is at the bottom of this answer

// Need a line to say if something if not all fields are filled
if( !uName || !pWord )
{
    alert( "Enter both a username and password" );
    return;
}

We use a return here to stop the rest of the function from executing

Full Code

function myFunction(){

    var uName = document.getElementById("uName").value;
    var pWord = document.getElementById("pWord").value;

    // Need a line to say if something if not all fields are filled
    if( !uName || !pWord )
    {
        alert( "Enter both a username and password" );
        return;
    }

    // This line controls the uName and pWord.

    if(uName == "Admin" && pWord == "Admin"){

        alert("Welcome " + uName);

        window.location.href="/pagetoredirectto.html";

    } else {
        alert( "User and Pass do not match" );
    }

}

Answer 3

Change your code as below and check:

function myFunction(){
    var uName = document.getElementById("uName").value;
    var pWord = document.getElementById("pWord").value;

    if(uName != "" && pWord != ""){ /* Ensure both fields have value */
        if(uName == "Admin" && pWord == "Admin"){
            alert("Welcome " + uName);
            /* Redirection code goes here */
        }else{
            /* If user is not Admin */
        }
    }else{
        /* Validation message goes here */
    }        
 }

Answer 4

Thats it i Hope:

 function myFunction(){ var uName = document.getElementById("uname").value; var pWord = document.getElementById("pWord").value; if (uName == "Admin" && pWord == "Admin") { // This line creates a pop-up with the name. alert("Welcome " + uName); // Need a line to redirect to a new page document.location = "http://www.google.de" // Need a line to say if something if not all fields are filled }else if (uName == "" || pWord == "") { alert("Fill all fields"); // Need a line with the else statement }else{ alert("Incorrect Combination"); } } 

 <input id="uname"></input> <input id="pWord"></input> <input type="button" onclick="myFunction()" value="Login"></input> 

Still a way to insecure Version of a login script.

If you go to debug you can see username and pass in cypher text plain insecurity.

Answer 5

You are taking reference of particular whole object in var pWord though you intend to take only value of password field.

Also You are assigning "Admin" to uName and pWord with the single = . For comparison use === or == though I would recommend use of === .

Do this:

function myFunction(){
    var uName = document.getElementById("uName").value;
    var pWord = document.getElementById("pWord").value;
}

For redirection use

window.location = "http://www.location.com/ie.htm";

Answer 6

Well try this example:

function myFunction(){
    var uName = document.getElementById("uName").value;
    var pWord = document.getElementById("pWord").value;

    // This line controls the uName and pWord.
    if(uName == "Admin" && pWord == "Admin"){
        // This line creates a pop-up with the name.
        alert("Welcome " + uName);
        // Need a line to redirect to a new page
        location.href = "http://www.SOMEURL.com";
        // Need a line with the else statement
    } else {
        // Need a line to say if something if not all fields are filled
        alert("Wrong input");
    }
}