Will it function properly if it is (NULL)?

Question

Will it function properly if it is (NULL)?

Here's the code snippet I'm currently using:

 <html>
    <head>
    <link type="text/css" rel="stylesheet" href="html.css" />
    <script type="text/javascript">
    function getName()
    {

    if(name)
    alert("Did you think I forgot about you, " + name + "?");
    else
    name=prompt("What's your name?","Please enter it here");


    }
    </script>
    </head>

    <body onload="var name;">
    <p onclick="getName()"; >Click here</p>
    </body>
    </html>

When I click the <p> text for the first time, it prompts me. However, if I click cancel without entering my name and then click the <p> text again, it doesn't prompt me anything.

Instead, it shows the name value as NULL. In C,

char a=NULL;
if(a)

evaluates to false. Does this same behavior occur in JavaScript?

javascript

Answer 1

Answer №1

It seems like you may come across an issue with setting the global variable name. When you set this, it actually affects the special property window.name, which persists even after refreshing the page.

To test this, try creating a page with the following script:

alert(window.name);
name = 'hello';

Initially, it will alert "undefined". However, upon refreshing the page, you should see "hello" instead.

To prevent this problem, consider renaming the variable name to something different.

Answer 2

It seems like you may come across an issue with setting the global variable name. When you set this, it actually affects the special property window.name, which persists even after refreshing the page.

To test this, try creating a page with the following script:

alert(window.name);
name = 'hello';

Initially, it will alert "undefined". However, upon refreshing the page, you should see "hello" instead.

To prevent this problem, consider renaming the variable name to something different.

Answer 3

Answer №2

give this a shot

if (name==undefined)
name=prompt("what is your name","enter here");
else
alert("did you think I would forget about you, " + name + "?");

Answer 4

give this a shot

if (name==undefined)
name=prompt("what is your name","enter here");
else
alert("did you think I would forget about you, " + name + "?");

Answer 5

Answer №3

This code snippet performs in the way you want, I believe: http://jsfiddle.net/YUCyL/5/

Upon observation, it appears that I have relocated the variable declaration to the beginning and updated its name to "username" instead of "name".

Answer 6

This code snippet performs in the way you want, I believe: http://jsfiddle.net/YUCyL/5/

Upon observation, it appears that I have relocated the variable declaration to the beginning and updated its name to "username" instead of "name".

Answer 7

Answer №4

This situation is quite complex.

The term "name" holds significance in the global window object, hence it should not be used as a variable due to potential unreliability.

If you modify it to something like name$, your code will function correctly.

Furthermore, it seems that "onload" necessitates an expression rather than a statement, which is why using it in that way may cause issues. The usage with name appears to work because it is preassigned.

Answer 8

This situation is quite complex.

The term "name" holds significance in the global window object, hence it should not be used as a variable due to potential unreliability.

If you modify it to something like name$, your code will function correctly.

Furthermore, it seems that "onload" necessitates an expression rather than a statement, which is why using it in that way may cause issues. The usage with name appears to work because it is preassigned.

Answer 9

Answer №5

<html>
<head>
<link type="text/css" rel="stylesheet" href="html.css" />
<script type="text/javascript">
var username;

function retrieveName() {
    console.log(username, typeof name);
    if(username && username !== 'null') {
        alert("Did you think I forgot about you, " + username + "?");
    } else {
        username=prompt("What's your name?", "Enter here");
    }
}
</script>
</head>

<body>
<p onclick="retrieveName()"; >Click here</p>
</body>
</html>

Looking at the output in the console, it appears that the username is a string with a null value. This may seem odd, but it seems like window.username converts the value to a string, in this case, null.

NOTE:

It's advisable not to use the term "username" as it might conflict with existing reserved terms (used as a property in window).

window.username will return a string representation of its stored value. For instance:

window.username = null;

window.username === 'null' true

window.username === null false

Answer 10

<html>
<head>
<link type="text/css" rel="stylesheet" href="html.css" />
<script type="text/javascript">
var username;

function retrieveName() {
    console.log(username, typeof name);
    if(username && username !== 'null') {
        alert("Did you think I forgot about you, " + username + "?");
    } else {
        username=prompt("What's your name?", "Enter here");
    }
}
</script>
</head>

<body>
<p onclick="retrieveName()"; >Click here</p>
</body>
</html>

Looking at the output in the console, it appears that the username is a string with a null value. This may seem odd, but it seems like window.username converts the value to a string, in this case, null.

NOTE:

It's advisable not to use the term "username" as it might conflict with existing reserved terms (used as a property in window).

window.username will return a string representation of its stored value. For instance:

window.username = null;

window.username === 'null' true

window.username === null false

Will it function properly if it is (NULL)?

Answer №1

Answer №2

Answer №3

Answer №4

Answer №5

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