qsopht

Simple Javascript to Limit Form Field lengths

The following javascript function does two things:

Checks the number of characters within a given form field (input textbox or textarea) and updates a div or span element.
Restricts the number of characters to the given maxlength.

function checkLength (elemId, showId, totalChars)
{
var elem = document.getElementById(elemId);
var elemShow = document.getElementById(showId);
var charsRem = totalChars – elem.value.length-1;
if (charsRem < 0)
{
elem.value = elem.value.substring(0,totalChars-1);
charsRem = totalChars – elem.value.length-1;
}
elemShow.innerHTML = charsRem;
}

Here is some sample html that shows how to use the above javascript:

<textarea id="txtBox" cols="75" rows="20" onkeypress="javascript: checkLength(‘txtBox’, ‘txtBoxShow’, 1000)"></textarea>
<br/> <span id="txtBoxShow">1000</span> characters remaining.

For some reason the form field length requires subtracting 1 from the total length. If anyone has an explanation let me know.

Here is a quick sample:

200 characters remaining.

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Sam @ October 24, 2007

Harry Potter Books Delivered by UPS

tech Comments (1)

My wife took these images today at work. The UPS truck was packed full of boxes full of “Harry Potter and the Deathly Hallows.”

The boxes (and the tape on the boxes) says “Do Not Open Before July 21st, 2007.”

Update: Thanks for the interest from metafilter.com. Interesting site.

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Sam @ July 17, 2007

Create a Simple User Login System with PHP and MySQL

code, mysql, php Comments (17)

First – The Demo

Here is all the code for the page – phplogin.php

<?php
session_start();
if ($_SESSION[‘loggedin’] == 1)
header("Location: loginsuccess.php");
if(isset( $Submit ))
{
$username="username";
$password="password";
$database="database";
mysql_connect("localhost",$username,$password);
@mysql_select_db($database) or die( "Unable to select database");
$username = $_POST[‘username’];
$password = $_POST[‘password’];
$query = "SELECT * FROM admin where username=\"$username\" and password = \"$password\" ";
$result = mysql_query($query);
$num = mysql_numrows($result);
if ($num > 0)
{
$_SESSION[‘loggedin’] = 1;
header("Location: loginsuccess.php");
} else {
$badlogin = 1;
}
}
if ($_GET[‘logout’] == "yes")
session_destroy();
?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en-US" lang="en-US">
<head><title></title></head>
<body>
<form name="form1" method="post" action="">
UserName: <input type="text" name="username" id="username" value="admin" />
Password: <input type="password" name="password" id="password" value="admin" /><Br />
<input type="submit" name="Submit" value="Submit" />
</form>
<?php
if ($badlogin == 1)
echo "<br/ ><span style=\"color: red;\">Invalid Login</span>";
?>
</body>
</html>

My user database table contains at least the following fields:
id, username, password

Add more fields as you see fit (last login time, address information, etc).

Here is a quick breakdown of the php code with comments:

//Required to use session variables
//This must be called at the beginning of each page in which you want to use the session variables
session_start();
//Check to see if we have already logged in successfully
//If login was successfully then redirect to appropriate page
if ($_SESSION[‘loggedin’] == 1)
header("Location: loginsuccess.php"); //php redirect
//This page posts to itself, so here to check to see if the page was submitted
if(isset( $Submit ))
{
//MySQL username and password
$username="username";
$password="password";
//Specify MySQL database to connect to
$database="database";
//Create connection and select the appropriate database
mysql_connect("localhost",$username,$password);
@mysql_select_db($database) or die( "Unable to select database");
//Get the username and password from posted form
$username = $_POST[‘username’];
$password = $_POST[‘password’];
//Build the query to look for users that exist with that username/password combination
//Here I’m using the admin table within my database
$query = "SELECT * FROM admin where username=\"$username\" and password = \"$password\" ";
//Retrieve the results of the query, and also aquire the number of records returned
$result = mysql_query($query);
$num = mysql_numrows($result);
//Check to see how many records are returned
if ($num > 0)
{
//User login was successful, set session variable then redirect to the loginsuccess.php page
$_SESSION[‘loggedin’] = 1;
header("Location: loginsuccess.php");
} else {
//Login was unsuccessful, set a local variable for later use
$badlogin = 1;
}
}
//Here we look for querystring variable called ‘logout’
//If logout exists, and is equal to ‘yes’ then call the php session_destroy() function
//This will essentially log out the user
if ($_GET[‘logout’] == "yes")
session_destroy();

Here is the actual html for the form (with comments for inline php)

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en-US" lang="en-US">
<head><title></title></head>
<body>
<form name="form1" method="post" action="">
UserName: <input type="text" name="username" id="username" value="admin" />
Password: <input type="password" name="password" id="password" value="admin" />
<input type="submit" name="Submit" value="Submit" />
</form>
<?php
//If login was unsuccessful then we want to show an error to the user.
if ($badlogin == 1)
echo "<br/ ><span style=\"color: red;\">Invalid Login</span>";
?>
</body>
</html>

That is all for this simple PHP/MySQL user login. If you need to ‘password protect’ any page within your site all you have to do at this point is add the following code to the top of the protected page:

session_start();
if ($_SESSION[‘loggedin’] != 1)
header("Location: phplogin.php");

This will check the session variable, and redirect to the login page if the variable hasn’t been set successfully.

Finally, to allow the user to logout simply create a link like this:

<a href="phplogin.php?logout=yes">Logout</a>

If you have any questions or suggestions feel free to leave a comment.
Thanks for visiting.

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Sam @ July 14, 2007

playing with light

tech Comments (0)

found an article on digg recently and starting playing around with light and long exposures. here are a few shots from that. they are all 10 second exposures. each light source is my phone. i tried laser, flashlight, led, and my phone. the phone worked out best.

1.
2.
3.

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Sam @ July 11, 2007

google the alphabet.

tech Comments (0)

I thought it would be interesting to see what happens when you google the alphabet. Here are the results.

	num results	top result
a	6,850,000,000	http://www.w3.org/tr/html4/struct/links.html
e	3,570,000,000	http://www.eonline.com/
s	3,450,000,000	http://en.wikipedia.org/wiki/Sulfur
i	3,420,000,000	http://www.ionline.tv/
t	3,200,000,000	http://www.mbta.com/
d	2,920,000,000	http://www.digitalmars.com/d/
c	2,630,000,000	http://en.wikipedia.org/wiki/C_(programming_language)
m	2,600,000,000	http://imdb.com/title/tt0022100/
o	2,430,000,000	http://en.wikipedia.org/wiki/Oxygen
n	2,200,000,000	http://www.the-n.com/
b	1,900,000,000	http://prb.aps.org/
w	1,630,000,000	http://www.starwoodhotels.com/whotels/index.html
x	1,610,000,000	http://www.x.org/
f	1,600,000,000	http://en.wikipedia.org/wiki/Fahrenheit
y	1,580,000,000	http://mail.yahoo.com/
v	1,520,000,000	http://vforvendetta.warnerbros.com/
k	1,470,000,000	http://en.wikipedia.org/wiki/K
r	1,450,000,000	http://www.r-project.org/
g	1,430,000,000	http://gmail.google.com/
j	1,360,000,000	http://www.jenniferlopez.com/
h	1,350,000,000	http://en.wikipedia.org/wiki/Hydrogen
z	1,230,000,000	http://www.nissanusa.com/z/
u	1,080,000,000	http://www.arizona.edu/
q	940,000,000	http://www.motorola.com/motoinfo/product/details/0,,113,00.html
p	139,000,000	http://www.december.com/html/4/element/p.html
l	131,000,000	http://en.wikipedia.org/wiki/Carolus_Linnaeus

Interestingly, if you google a you get about 6,850,000,000 results, but if you google “a” then about 7,260,000,000 results are found. I wonder why?

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Sam @ March 10, 2007

How exercising causes global warming.

general Comments (2)

We must breathe the air around us in order to live. Carbon dioxide is released as we exhale. Plants then take this carbon dioxide and produces oxygen. Hey look, it’s a cycle. This cycle assumes that humans produce only a certain level of carbon dioxide.

Exercising causes us to breathe more frequently, thus producing more carbon dioxide than normal. You can test this in your own home. If you have stairs, run up them, then back down. Repeat. You should notice that you are now producing more carbon dioxide than in a resting state. Many reports have noted that rising carbon dioxide gas in the atmosphere (which can be caused by running, biking, lifting weights) is causing global warming across the world.

Think you are doing good by running daily? Think again. The world would appreciate it if you would relax and watch a bit of TV. Why must it always be about you?

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Sam @ February 27, 2007