function copyDown(nm) {
// written by Daniel P 3/20/07
// repeat the values of the first row of a column down the whole column
// special case for sku: value in incremented as you go down.
// also, values are only filled in for rows that have a sku filled in
	var lastskuindex = document.getElementById('lastindex');
	var firstitem = document.getElementById(nm+'0');
	z = firstitem.value;
	for ( i=1; i<=lastskuindex.value; i++ ) {
		//window.receivelist["Received"+i].checked=true;
		if (nm=='SKUCode' && z!='') {	// special case for skucode (when not blank)
			z++;	// increments the sku
			zstring = z.toString();
			if ( zstring.length == 1 )	zstring='00000'+zstring;
			if ( zstring.length == 2 )	zstring='0000'+zstring;
			if ( zstring.length == 3 )	zstring='000'+zstring;
			if ( zstring.length == 4 )	zstring='00'+zstring;
			if ( zstring.length == 5 )	zstring='0'+zstring;
			document.getElementById(nm+i).value = zstring;
		} else {
			if (document.getElementById('SKUCode'+i)) {	// if there's an editable skucode (only add page)
				if (document.getElementById('SKUCode'+i).value != '') {	// only update this row if sku is filled in for this row
					document.getElementById(nm+i).value = firstitem.value;
				}
			} else {	// not add page, so we just update regardless of if sku is filled in
				document.getElementById(nm+i).value = firstitem.value;
			}
		}
	}	// looping down the rows
}

#include <iostream>
#include <fstream>
#include <string>
using namespace std;

int main()
{
	
	ifstream inputFile;
	string line;
	string input;

	cout << "Enter a file name to scan" << endl;
	cin >> input;

	cout << endl;
	cout << "Your file was: " << input << endl;
	
	try {
		inputFile.open(input.data(), ios::in);
	}
	catch (...) {
		cout << "File open error" << endl;
	}

	if ( !inputFile.is_open() ) {
		return -1;
	}

	while (! inputFile.eof() )
    {
      getline(inputFile, line, ' ');
	  cout << "__________ " << line << endl;
    }

	inputFile.close();

	
	cin >> input; // Just used to keep the console open in Visual C++
	return 0;
}

/** @id codeFocus 
* @classDescription Focuses on the selected input and selects the value text. 
*/
var postcodeFocus = {
	grab:function(){
		if(!document.getElementById){return;};
		if(!document.getElementById('selected')){return;};
		var theInput = document.getElementById('selected');
		theInput.focus();
		theInput.select();
	}
}

$("input[name=forname], input[name=surname]").focus(function(){
	var defaultText = $(this).val();
	if(defaultText === "Forename" || defaultText === "Surname"){
		$(this).select();
	}
});

<div id="searchbar">
 <form action="http://domain.com/search" method="get"> 
  <input type="text" name="q" value="Search Our Site" size="20" maxlength="120" id="searchInput" onfocus="if(this.value == 'Search Our Site'){this.value='';}">
  <input type="hidden" name="site" value="externalSearch">                    
  <input type="hidden" name="client" value="externalSearch">                  
  <input type="hidden" name="restrict" value="wwwexternal">  
  <input type="hidden" name="proxystylesheet" value="http://domain.com/searchStyle.xslt">                                             
  <input type="hidden" name="output" value="xml_no_dtd">     

  <input type="submit" name="btnG" value="Search" id="searchSubmit">
 </form>
</div>

	$('.default-value').each(function() {
    	var default_value = this.value;
    	$(this).focus(function() {
        	if(this.value == default_value) {
            	this.value = '';
        }
    });
    $(this).blur(function() {
        if(this.value == '') {
            this.value = default_value;
        }
    });

/*
+-------------------------------------------------------------------+
|______________________The_Sterilizer_Function______________________|
| PHP 5+ ONLY - Used to prevent SQLI and XSS attacks via user input |
|                                                                   |
| 1 *REQUIRED* value, 1 <OPTIONAL> value to call this function:     |
|   $input  = User input string to be cleansed                      |
|   #is_sql = Boolean. Whether or not $input is a sql query         |
+-------------------------------------------------------------------+
| Example of use:                                                   |
|   $username = sterilize($_POST['username']);                      |
|   $query = "SELECT * FROM users WHERE username = '$username'";    |
+-------------------------------------------------------------------+
*/

function sterilize ($input, $is_sql = false)
{
    $input = htmlentities($input, ENT_QUOTES);

    if(get_magic_quotes_gpc ())
    {
        $input = stripslashes ($input);
    }

    if ($is_sql)
    {
        $input = mysql_real_escape_string ($input);
    }

    $input = strip_tags($input);
    $input = str_replace("
", "\n", $input);

    return $input;
}

$('input#ID').keyup(function(){
   $('div-where-the-text-will-show').text($(this).val());
});

$("input, textarea").focus(
		 function()
		 {
		  // only select if the text has not changed
		  if(this.value == this.defaultValue)
		  {
		   this.select();
		  }
		 }
		)

Regarding user input (e.g. web forms, but pretty much any possible user input):

Check the length of the input to verify that it is less than your max (always set some sort of maximum) and greater than zero.

In PHP with MySQL, use the function "mysql_real_escape_string" when interacting with the database (db).

Always clean your output (to prevent XSS, or Cross-Site Scripting):
In PHP, you can use the functions "htmlentities" for textual output and "urlencode" for URI's.

Never accept user input for filenames! Write your own filename, perhaps based on pre-cleaned user input, but preferably just an alphanumeric name of your choice (which can be stored in the db for reference). And before you write the file, use the PHP functions "basename" and "realpath" (i.e. basename(realpath($filename)) ) in order to establish exactly where the file would end up if you do write it as is. Also very important: before creating the file, use the PHP function "umask," i.e. umask(077), so that files have their permissions locked down before they are created. This prevents someone from accessing the file before you have time to manually change the permissions.

Whenever a user logs in, use the PHP function "session_regenerate_id" to prevent fraudulent access to their account or a session-fixation attack.

More to come... Please post your own.