PHP: Determine whether its a checkbox is checked or not -

my checkbox looks this:

<input type="checkbox" name="activate[]" class="setsetting" value="<?php echo $row["id"]; ?>"> 

and have foreach:

$activate = $_post['activate'];          foreach($activate $a){         echo $a ."<br>";         } 

works fine value out of. how can determine if checkbox has been checked?

$activate = $_post['activate'];          foreach($activate $a){         $query_email = mysql_query("select id lp_email_settings order id asc");             while($ro = mysql_fetch_row($query_email)){             $getusersettings = mysql_query("select * users_email_settings uid = '$user' , esetting = '$ro[0]'");                 if($ro[0] == $a){                     if(mysql_num_rows($getusersettings) != 1){                     mysql_query("insert users_email_settings (uid, esetting) values ($user, $ro[0])");                     }                 }else{                 mysql_query("delete users_email_settings uid = '$user' , esetting = '$ro[0]'");                 }             }             echo $a."<br>";         } 

only checkboxes submitted considered successful (i.e. checked). means checked checkboxes available in $_post['activate'].

and determine whether checkbox has been checked, can use array_search check whether particular id value in $_post['activate']:

array_search('12345', $_post['activate'], true) 

and if change control’s name use id key this:

<input type="checkbox" name="activate[<?php echo $row["id"]; ?>]" class="setsetting" value="<?php echo $row["id"]; ?>"> 

then can use isset or array_key_exists on $_post['activate']:

isset($_post['activate']['12345']) array_key_exists('12345', $_post['activate']) 

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edit    as said in comments, should rather iterate available options , check each option whether it’s active , needs activated or deactivated. can follows:

$activate = array_flip($_post['activate']); $query = "select t1.id, t2.esetting           lp_email_settings t1 left outer join users_email_settings t2 on (t1.id = t2.esetting)           order t1.id asc"; $result = mysql_query($query); $insert = array(); $delete = array(); while ($row = mysql_fetch_row($result)) {     if ($row[1] === null) {         // option not set yet         if (isset($activate[$row[0]])) {             // option needs set             $insert[] = $row[0];         }     } else {         // option set         if (!isset($activate[$row[0]])) {             // option needs unset             $delete[] = $row[0];         }     } } if (!empty($insert)) {     $query = "insert users_email_settings (uid, esetting)               values ($user, " . implode("), ($user, ", $insert) . ")";     mysql_query($query); } if (!empty($delete)) {     $query = "delete users_email_settings               uid = $user , esetting in (" . implode(", ", $delete) . ")";     mysql_query($query); } 

the first query select left join of available options , active options. result set id of option in first column , second column either null if options not active or otherwise again id. if there 3 options (e.g. 1, 2, , 3) , options 1 , 3 set, result should this:

 id | esetting ----+----------   1 |        1   2 |     null   3 |        3 

so if $row[1] null (inactive option), id in $row[0] added $insert array if corresponding option set in request ($activate[$row[0]], keys/values flipped have direct access). same done options active not set in request.

at end collected options in $insert inserted , in $delete removed.