can't get my fnction cback to work

dater59S

http://debbiet.x10.mx/hour17_telltime.html

can someone take a look at this and tell me what I am doing wrong. When I click the make call I don't get the time to work?

bradgrafelman

First problem I see is the error in my Javascript console:

Uncaught TypeError: Object #<Document> has no method 'getElementByTagName'

dater59S

Hello,
I'm sorry but I am new at this and I am typing from a book the scripts. I'm not sure where you are talking about. I have gone over and over what the book is showing to no avail. I know this must be old hat to you.
I checked the html file on the getElementByTagName and it is exactly like the book show me.
Can you tell me where I made the error

traq

If "the book" describes a function named [font=monospace]getElementByTagName[/font], then it either:

a) wrote its own function named [font=monospace]getElementByTagName[/font]. Find the function definition and add it to your code.

b) misspelled the name of the native javascript function [font=monospace]getElementsByTagName[/font]. Correct the spelling.

bradgrafelman

You'll also want to check the character case on "childnodes" (did you mean childNodes?) and "nodevalue" (did you mean nodeValue?).

dater59S

there is a php file

<?php
header('Contnt-Type: text/xml');
echo "<?xml version=\"1.0\" ?><clock1><timenow>" .date('H:i:s:')."</timenow></clock1>";
?>

Is this what you are talking about

dater59S

sorry I see the s misspelling. I fixed that

dater59S

<script src="myAjaxLib.js"></script>
<script>
	function cback(text) {
		var servertime = text.getElementsByTagName("timenow")[0].childnodes[0].nodevalue;
		alert('Server time is ' + servertime);
	}
	window.onload = function() {
		document.getElementById("btn1").onclick = function () {
			doAjax("telltimeXML.php", "", "cback", "POST", 1);
		}
	}
	</script>

bradgrafelman

See my reply above. Also, please use the board's bbcode tags when posting code.

EDIT: Also note that "Content" is misspelled in your PHP file.

dater59S

Thank you so much. I think I was just on this computer too long. Do you have any suggestions on what program to use to help with the entry. Typo's? I didn't get any errors when running it.
Also I have apache2 installed and I put all the files in htdocs and I can't get it to work there. I have it on a hosting site and it now runs but not on local?
I thought apache would solve the issue?

johanafm

I use PhpStorm which handles javascript as well. If you do not need the php-side of it, they also have an IDE called WebStorm, but I don't really know what differences there might be between those two applications though. Apart from code completion they have support for jshint / jslint which will enforce you to write good javascript code. It may be a bit more work initially, but it is definitely worth it. There are things you are better off learning sooner rather than later.

You'd have to check that apache is running and is properly configured. Apache may not be running. It may not be listening on port 80. It may not be configured to map to your htdocs folder. It may not treat .php files as php files. If you point your browser to localhost/your-php-file-for-server-time, what output do you get? Are there any error messages in your apache log file?

I'd also check the publish date on your book. While it may be that they will get to these things later, it could also be that the book is using ways of doing things that you should not (generally) do. If they don't deal with these topics at all, I'd advice you to find another source of information. For example, adding event handlers by property assignment will overwrite any existing event handlers for that object.

window.onload = previousHandlersErased;
someDOMNode.click = previousHandlersErased;

Another example is that it may be suitable from a teaching perspective to deal with XML documents. However, if your server sends content intended for non-human processing, it'd be better to use JSON. I.e.
serverside

echo json_encode(array('server-time' => date('H:i:s:')));

clientside

function cback(text) {
	alert('Server time is ' + JSON.parse(text)['server-time']);
}

However, JSON.parse was added in javascript 1.7 and may not exist in older browsers.

And you'd be well adviced to NOT end your php files with a php closing tag. Php parsing will end at end of file if the closing tag is missing. If it is present, you risk adding white-space output.

<?php
guaranteed_no_trailing_whitespaces_output();

<?php
trailing_whitespace_output();
?>