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Question

How to start a marquee with JavaScript based on user input?

Answer 1

+1 A:

var text = document.getElementById(namebox).value;

N 1.1 2010-03-18 01:25:20

P.s. do read about unobtrusive javascript.

N 1.1 2010-03-18 01:30:34

Answer 2

+1 A:

You probably don't want to use document.write for this-- use document.createElement('marquee') to create the element, and then add it to the body of the page. You can set attributes like direction on the element you get back, and set its innerHTML to the text you want in the marquee.

(P.S. Marquee? Really?)

quixoto 2010-03-18 01:26:29

ya seriously! marquee?

N 1.1 2010-03-18 01:29:56

Yep really. Marquees aren't my favorite either, but I'm doing this for a competition with one of my friends.

APShredder 2010-03-18 01:37:13

@APShredder: competition. Good.

N 1.1 2010-03-18 01:38:52

Answer 3

+3 A:

Your JavaScript has a few problems.

You are passing an undefined variable namebox to getElementById. You need to put this in quotes ('namebox').
You need to check the value of text against the empty string, not null.
You need to use the value of the input (text.value as opposed to just text) in the element you're creating.

Here is what your code would look like with these fixes:

function StartMarquee() {
  var text = document.getElementById('namebox');
  if (text.value !== '') {
    document.write("<marquee behavior='scroll' direction='right'>Hello " + text.value + "!</marquee>");
  }
  else {
    alert("Enter your name first!!!");
  }
}

Some other general suggestions:

Don't use document.write. Instead, use DOM methods to create a new element and insert it into the DOM.
Use unobtrusive JavaScript. Attach your behavior after the document loads instead of using inline event handlers.
Use === and !== for conditions to avoid type coercion and to ensure you're getting the result you think you are.
Never, ever use marquee.

Jimmy Cuadra 2010-03-18 01:39:01

+1 for Never, ever use marquee.

TiansHUo 2010-03-18 02:22:16

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How to start a marquee with JavaScript based on user input?

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