phpforfun

I am making a game with PHP and ajax but I have an issue. When a player joins a queue their user id is inserted into a database field called users. But when users either logout, close the browser, just leave the game in some form of way I need their id to be removed from that field. I know there is jquery .unload function but how reliable is that really? So could anyone help me in finding a reliable way of removing the user id from the field when they leave the game? thanks

So should I make a different token for each form or can one token be used for all the forms?

Hey guys I am new to CSRF attacks and would like to know a little more about it. So I was messing with my code and here is what happened There is 2 pages, demo.php and edit_account.php demo.php and edit_account.php have the same exact form but the demo.php forms action value is edit_account.php. edit_account.php is where the database and everything gets updated. So when I submited the form on demo.php it went to edit_account.php and updated the database and everything because they have the same form names etc. So is this considered a CSRF attack and does this mean I need to put a "token" or whatever they do to protect from these attacks on EVERY form; because some hacker can just make a fake website, copy the form from inspect element and put it on their website and be updating the data on another website without even them knowing. Example form code that I tested and this attacked worked. <form action="edit_account.php" method="POST"> <br><br><table style="width:60%"> <tr> <td><font style="font-size:22px;font-weight:bold;">Birthday:</font></td> <td> <label class="a"><select name="birth_day"><option value='0'>Day</option><option value="1">1</option> <option value="2" selected>2</option> <option value="3">3</option> <option value="4">4</option> <option value="5">5</option> <option value="6">6</option> <option value="7">7</option> <option value="8">8</option> <option value="9">9</option> <option value="10">10</option> <option value="11">11</option> <option value="12">12</option> <option value="13">13</option> <option value="14">14</option> <option value="15">15</option> <option value="16">16</option> <option value="17">17</option> <option value="18">18</option> <option value="19">19</option> <option value="20">20</option> <option value="21">21</option> <option value="22">22</option> <option value="23">23</option> <option value="24">24</option> <option value="25">25</option> <option value="26">26</option> <option value="27">27</option> <option value="28">28</option> <option value="29">29</option> <option value="30">30</option> <option value="31">31</option> </select></label><label class='a'><select name='birth_month'><option value="1">Month</option> <option value="2">January</option> <option value="3">February</option> <option value="4">March</option> <option value="5">April</option> <option value="6">May</option> <option value="7">June</option> <option value="8">July</option> <option value="9">August</option> <option selected="selected" value="10">September</option> <option value="11">October</option> <option value="12">November</option> </select></label><label class='a'><select name='birth_year'> <option value='private'>Year</option><option value="1900">1900</option> <option value="1901">1901</option> <option value="1902">1902</option> <option value="1903">1903</option> <option value="1904">1904</option> <option value="1905">1905</option> <option value="1906">1906</option> <option value="1907">1907</option> <option value="1908">1908</option> <option value="1909">1909</option> <option value="1910">1910</option> <option value="1911">1911</option> <option value="1912">1912</option> <option value="1913">1913</option> <option value="1914">1914</option> <option value="1915">1915</option> <option value="1916">1916</option> <option value="1917">1917</option> <option value="1918">1918</option> <option value="1919">1919</option> <option value="1920">1920</option> <option value="1921">1921</option> <option value="1922">1922</option> <option value="1923">1923</option> <option value="1924">1924</option> <option value="1925">1925</option> <option value="1926">1926</option> <option value="1927">1927</option> <option value="1928">1928</option> <option value="1929">1929</option> <option value="1930">1930</option> <option value="1931">1931</option> <option value="1932">1932</option> <option value="1933">1933</option> <option value="1934">1934</option> <option value="1935">1935</option> <option value="1936">1936</option> <option value="1937">1937</option> <option value="1938">1938</option> <option value="1939">1939</option> <option value="1940">1940</option> <option value="1941">1941</option> <option value="1942">1942</option> <option value="1943">1943</option> <option value="1944">1944</option> <option value="1945">1945</option> <option value="1946">1946</option> <option value="1947">1947</option> <option value="1948">1948</option> <option value="1949">1949</option> <option value="1950">1950</option> <option value="1951">1951</option> <option value="1952">1952</option> <option value="1953">1953</option> <option value="1954" selected>1954</option> <option value="1955">1955</option> <option value="1956">1956</option> <option value="1957">1957</option> <option value="1958">1958</option> <option value="1959">1959</option> <option value="1960">1960</option> <option value="1961">1961</option> <option value="1962">1962</option> <option value="1963">1963</option> <option value="1964">1964</option> <option value="1965">1965</option> <option value="1966">1966</option> <option value="1967">1967</option> <option value="1968">1968</option> <option value="1969">1969</option> <option value="1970">1970</option> <option value="1971">1971</option> <option value="1972">1972</option> <option value="1973">1973</option> <option value="1974">1974</option> <option value="1975">1975</option> <option value="1976">1976</option> <option value="1977">1977</option> <option value="1978">1978</option> <option value="1979">1979</option> <option value="1980">1980</option> <option value="1981">1981</option> <option value="1982">1982</option> <option value="1983">1983</option> <option value="1984">1984</option> <option value="1985">1985</option> <option value="1986">1986</option> <option value="1987">1987</option> <option value="1988">1988</option> <option value="1989">1989</option> <option value="1990">1990</option> <option value="1991">1991</option> <option value="1992">1992</option> <option value="1993">1993</option> <option value="1994">1994</option> <option value="1995">1995</option> <option value="1996">1996</option> <option value="1997">1997</option> <option value="1998">1998</option> <option value="1999">1999</option> <option value="2000">2000</option> <option value="2001">2001</option> <option value="2002">2002</option> <option value="2003">2003</option> <option value="2004">2004</option> <option value="2005">2005</option> <option value="2006">2006</option> <option value="2007">2007</option> <option value="2008">2008</option> <option value="2009">2009</option> <option value="2010">2010</option> <option value="2011">2011</option> <option value="2012">2012</option> <option value="2013">2013</option> <option value="2014">2014</option> <option value="2015">2015</option> </select></label> <br><br>

Hey guys, So I wanted to know what security measures I would have to take when retrieving user information from the database with the $_GET method. The $_Get would be the user_id so do I need to add some if statements to make sure its an integer, not empty etc. And what function would I use for in case of the user attempts to break the website by changing the url with commas,malicious code, etc.