使用javascript和php增加值并将其保存在POST数组中

I am incrementing a value of a hidden element using javascript , and posting it in the $_POST array. But it increases only once , and then remains the same. Please help.

My file is incrementing.php with the below code:

<script language="Javascript">

function NextClicked()
{  
 document.getElementById("LabelClicked").value = 
  document.getElementById("LabelClicked").value + 1 ; 

 document.forms["incrementing"].submit();

}
</script>


<?php

if(isset($_POST['LabelClicked']) && $_POST['LabelClicked']>=1)
{
  $_POST['LabelClicked'] = $_POST['LabelClicked'] +9; 

}

?>
<?php
    if(isset($_POST['clickednext']))
    {
        echo 'Value ='.$_POST['LabelClicked'];
    }
    else
    {
        echo "Not Clicked Yet";
    }   
?>
<form name = "incrementing" method="post" action="incrementing.php">
 <div class=d2 align=left><a href="#" onclick=" NextClicked(); submit();">Next</a>
<input type = "hidden"  id="LabelClicked" name="LabelClicked" />
</form>

Don't you need to set the value of LabelClicked id to be what the new, incremented value is?

<input type="hidden"  id="LabelClicked" name="LabelClicked" value="<?php echo $_POST['LabelClicked']; ?>" />

Otherwise it is incrementing from "" everytime. You should also make sure that you are treating

document.getElementById("LabelClicked").value

as an integer and not a string, or else you will get "111111"