html - How to Print a variable in a function in PHP -

i have form, post="modelselector", when submitted, go through these codes. issue i'm facing is, want check value of $_post, know getting set calling "isset()".

i want print/alert/pushout variable $productselection

function selectproduct() {            // save post in variable     $productselections =  $_post['modelselector'];      // want print $productselection check value     $frmvars['productselections'] = $productselections;     $frmvars['windowsize']        = $windowsize;     $frmvars['pagenum']  = 1;     saveformvalues(0,'rundefmgr', $frmvars);      // clear checkboxes              $sel = array();     deleterundef(0,"*","run_def_edit","*"); }   if(isset($_post['modelselector'])) {     selectproduct(); }  

i have tried echo, reason not printing value in html. in advance.

i want check value of $_post

$_post array.

use print_r($_post) or var_dump($_post) view contents.