PHP string and process control methods

<?php 
$init = $_POST["init"];//game restart 
$clickvalue = $_POST["clickvalue"];//minesweeping 
$checkflag = 0;//Victory or defeat 
$click_count = 0;//clicks count 
if($init == null && $clickvalue == null){//initialization 
  $_POST = array();//set POST with a array 
  $_POST["rows"] = 9;//set rows 
  $_POST["cols"] = 9;//set cols 
  $_POST["num"] = 10;//set num 
  $_POST["timeshow"] = "00:00"; //set starttime 
  $init = true;//set initialization 
} 
$rows = $_POST["rows"];//get rows 
$cols = $_POST["cols"];//get cols 
$num = $_POST["num"];//get num 
$starttime = $_POST["starttime"];//get starttime 
if($init){// is initialization 
  $timeshow = "00:00";//set starttime 
  $data = array();//data initialization 
  for($i=0;$i<$rows;$i++){//all the rows 
    for($j=0;$j<$cols;$j++){//all the cols 
      $data["data".$i."_".$j] = 0;//set mine with null 
      $data["open".$i."_".$j] = 0;//set node with close 
    } 
  } 
  $i=0;//reset the index,and set the mines(Random setting) 
  while($i < $num){//number of mine 
    $r = rand(0,$rows - 1);//row&#39;s index 
    $c = rand(0,$cols - 1);//col&#39;s index 
    if($data["data".$r."_".$c] == 0){//if not a mine 
      $data["data".$r."_".$c] = 100;//set the node with a mine 
      $i++; 
    } 
  } 
  for($i=0;$i<$rows;$i++){//all the rows 
    for($j=0;$j<$cols;$j++){//all the cols 
      if($data["data".$i."_".$j] == 100)continue;
      //is not a mine , set number of adjacent mines  
      $cnt = 0; 
      if($i - 1 >= 0 && $j - 1 >= 0 && $data["data".($i - 1)."_".($j - 1)] == 100)$cnt++;//upper left 
      if($i - 1 >= 0 && $data["data".($i - 1)."_".$j] == 100)$cnt++;//left 
      if($i - 1 >= 0 && $j + 1 < $cols && $data["data".($i - 1)."_".($j + 1)] == 100)$cnt++;//lower left 
      if($j - 1 >= 0 && $data["data".$i."_".($j - 1)] == 100)$cnt++;//upper 
      if($j + 1 < $cols && $data["data".$i."_".($j + 1)] == 100)$cnt++;//lower 
      if($i + 1 < $rows && $j - 1 >= 0 && $data["data".($i + 1)."_".($j - 1)] == 100)$cnt++;//upper right 
      if($i + 1 < $rows && $data["data".($i + 1)."_".$j] == 100)$cnt++;//right 
      if($i + 1 < $rows && $j + 1 < $cols && $data["data".($i + 1)."_".($j + 1)] == 100)$cnt++;//lower right 
      $data["data".$i."_".$j] = $cnt;//set number 
    } 
  } 
}else{ 
  $data = $_POST;//get data 
  if($data["data".$clickvalue] == 100){
  //check the value of users click 
    $checkflag = 2;//if click on a mine,gameover 
    for($i=0;$i<$rows;$i++){//all the rows 
      for($j=0;$j<$cols;$j++){//all the cols 
        $data["open".$i."_".$j] = 1;
        //set all nodes to open 
      } 
    } 
  }else{ 
    $node = explode("_", $clickvalue);//get the node of click 
    openNode($node[0],$node[1]);//set nodes to open 
    for($i=0;$i<$rows;$i++){//all the rows 
      for($j=0;$j<$cols;$j++){//all the cols  
        if($data["open".$i."_".$j] == 1)$click_count++;
        //get the number of opennode  
      } 
    } 
    if($rows*$cols - $click_count == $num)$checkflag = 1;
    //if all the node is open,game clear  
  } 
} 
if($checkflag == 0 && $click_count == 1){
//if game is start ,time start 
  $starttime = date("H:i:s"); 
} 
if($starttime){//Computing time and display 
  $now = date("H:i:s"); 
  $nowlist = explode(":",$now); 
  $starttimelist = explode(":",$starttime); 
  $time_count = $nowlist[0]*3600+$nowlist[1]*60 + $nowlist[2] - ($starttimelist[0]*3600+$starttimelist[1]*60 + $starttimelist[2]);
  $min = floor($time_count / 60); 
  $sec = $time_count % 60; 
  $timeshow = ($min>9?$min:"0".$min).":".($sec>9?$sec:"0".$sec); 
}else{ 
  $timeshow = "00:00";//if game is stop , time stop 
} 
function openNode($i,$j){//set nodes to open,if it is can open 
  global $rows;//get the rows 
  global $cols;//get the cols 
  global $data;//get the data 
  if($i < 0 || $i >= $rows || $j < 0 || $j >= $cols || $data["open".$i."_".$j])return;
  //it is not a node,or it has been opened 
  $data["open".$i."_".$j] = 1;//open the node 
  if($data["data".$i."_".$j] > 0)return;//need to continue? 
  openNode($i - 1,$j - 1); 
  openNode($i - 1,$j); 
  openNode($i - 1,$j + 1); 
  openNode($i,$j - 1); 
  openNode($i,$j + 1); 
  openNode($i + 1,$j - 1); 
  openNode($i + 1,$j); 
  openNode($i + 1,$j + 1); 
} 
?> 
<html> 
<head> 
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /> 
<title>扫雷游戏</title> 
</head> 
<body> 
<form action="" method="post"> 
<input type="hidden" name="starttime" value="<?php echo $starttime;?>"/> 
<input type="hidden" name="clickvalue"/> 
<table style="top:10px;left:0px;z-index:0;margin:10px auto" border="1px"> 
<tr> 
<td width="100px" align="center"> 
  <table width="100%" border="1px"> 
    <tr><td>行数:</td><td><input type="text" name="rows" value="<?php echo $rows;?>" size="1"/></td></tr> 
    <tr><td>列数</td><td><input type="text" name="cols" value="<?php echo $cols;?>" size="1"/></td></tr> 
    <tr><td>雷数:</td><td><input type="text" name="num" value="<?php echo $num;?>" size="1"/></td></tr> 
    <tr><td colspan="2" align="center"><input type="submit" value="重新开始" name="init"/></td></tr> 
  </table> 
</td> 
<td width="50px" align="center"><font size="10px"><?php echo $checkflag < 2?"☺":"☹";?></font></td> 
<td width="100px" align="center"> 
<?php  
  if($checkflag == 1)echo "恭喜，雷全部清掉了!<br />"; 
  else if($checkflag == 2)echo "太挫了，又被雷炸死了<br />"; 
?> 
  <input type="text" name="timeshow" value="<?php echo $timeshow;?>" size="4" readonly > 
</td> 
</tr> 
</table> 
<table style="top:155px;left:0px;z-index:0;margin:10px auto" border="1px"> 
<?php for($i=0;$i<$rows;$i++){ ?> 
  <tr> 
  <?php for($j=0;$j<$cols;$j++){  ?> 
    <td style="width:24px;height:24px;" align="center"> 
    <input type="hidden" name="open<?php echo $i."_".$j;?>" value="<?php echo $data["open".$i."_".$j];?>"> 
    <input type="hidden" name="data<?php echo $i."_".$j;?>" value="<?php echo $data["data".$i."_".$j];?>"> 
    <?php if($data["open".$i."_".$j]){//show the value of node,if the node has been opened ?> 
      <?php echo $data["data".$i."_".$j]==100?"☀":$data["data".$i."_".$j];?> 
    <?php }else{//show a button ,if the node has not been opened ?>
      <input type="button" value="" onclick="clickNum(&#39;<?php echo $i."_".$j;?>&#39;)" style="width:20px;height:20px;"> 
    <?php } ?> 
    </td> 
  <?php } ?> 
  </tr> 
<?php } ?> 
</table> 
</form> 
<script type="text/javascript"> 
function clickNum(value){//click a node 
  <?php if($checkflag > 0)echo &#39;return;&#39;;//if game is clear or game is over ?> 
  document.forms[0].clickvalue.value = value; 
  document.forms[0].submit(); 
} 
<?php if($checkflag == 0 && $click_count>0)echo &#39;setTimeout("timerun()",1000);&#39;;//time running ?> 
<?php if($checkflag == 1)echo &#39;alert("恭喜，雷全部清掉了!");&#39;;?> 
<?php if($checkflag == 2)echo &#39;alert("太挫了，又被雷炸死了");&#39;;?> 
function timerun(){//time running 
  var timelist = document.forms[0].timeshow.value.split(":"); 
  var sec = parseInt(timelist[1],10) + 1; 
  var min = sec < 60?parseInt(timelist[0],10):(parseInt(timelist[0],10) + 1); 
  document.forms[0].timeshow.value = (min>9?min:"0"+min)+":"+(sec > 9?sec:"0"+sec); 
  setTimeout("timerun()",1000); 
} 
</script> 
</body> 
</html>