PHP - Php 8's Attribute Feature Converted To Php 7 Compatible Attributes.

Hey all, I am not familiar with php coding at all and was wondering if anyone could help me re-code the below to being php 7 compatible. After using a php testor, it says mysql_connect is deprecated and needs to use the alternative mysqli_connect instead. How would I rewrite the below to be in the mysqli_connect format? Thank you in advance

<?php

$db = "MyDatabaseName"; //set this to the name of your database
$host = "localhost"; //set this to the name of your host
$user = "MyUserName"; //set this to your db user name
$pass = "MyPassword"; //set this to your db password
$con = mysql_connect("$host","$user","$pass");
$table = "MyDatabaseTableName"; //set this to the name of the table that holds the card info.

$con= mysql_connect("$host","$user","$pass");
if(!$con)
{
  $connect_error = "Failed at mysql_connect. ";
  echo"error at db connect";
  exit();
}

$tablewidth = "490";//set the main table width on the spread pages with this.
$imagedirectory = "images/"; //main image directory
$largeimagedirectory = "images/medium/";

srand((double)microtime()*1000000);

?>

PLEASEEE no matter what  i do... datepicker always post the dates as string i do whatever ways know convert string to date but no way!! how convert string to date so i can sarch in a mysql table... tnx in advanced 

    <!--HTML-->

    <div class="control-group">
        <label class="control-label">from</label>
        <div class="controls input-append date form_date" data-date="" data-date-format='yyyy/mm/dd' data-link-format="yyyy/mm/dd">
        <input size="16" type="text" value="" id="from" name="from">
        <span class="add-on"><i class="icon-th"></i></span>
    </div>
        <input type="hidden" id="d" value="" /><br/>
    </div>
    <div class="control-group">
        <label class="control-label">tto</label>
        <div class="controls input-append date form_date" data-date="" data-date-format='yyyy/mm/dd' data-link-format="yyyy/mm/dd">
        <input size="16" type="text" value="" id="tto" name="tto">
        <span class="add-on"><i class="icon-th"></i></span>
    </div>
        <input type="hidden" id="h" value="" /><br/>
    </div>
    <div class="card-body">        
        <button type="submit" class="btn btn-secondary">search...</button>
    </div>

    <!--PHP-->

    $yfromx=$_POST['from']  ;
    $yuntilly=$_POST['untill']  ;
    $yfroma=str_replace(" ","/","$yfromx");
    $yuntillb=str_replace(" ","/","$yuntilly");

    $t1=gettype ( $yfromx ) ;
    $t2=gettype ( $yuntilly ) ;
    $yfrom=date('Y/m/d', '$yfroma');
    $yuntill=date('Y/m/d', '$yuntillb');
    $t3=gettype ( $yfrom ) ;
    $t4=gettype ( $yuntill ) ;
    echo $yfroma.' | '.$yuntillb.' | '.$t1.' | '. $t2.' | '.$t3.' | '. $t4;
    //SELECT username FROM oc_calendar WHERE start_date between '$from' AND '$to'
    $queryfebus = "SELECT distintc FROM glamm_pedidos WHERE fecha_folio between '$yfrom' AND '$yuntill';";
    //$queryfolb = "SELECT *M glamm_pedidos WHERE procesado='$yfoliox' or folio='$yfoliox' or nombre like '%$yfoliox%' or mail like '%$yfoliox%';";
    $resultfebus = mysqli_query($con,$queryfebus) or mysqli_error($con);
    blah 
    blah

I am preparing $begin and $end for DatePeriod() but I can't get passed this error "getting the error Recoverable fatal error: Object of class DateTime could not be converted to string".

$today = date("Y-m-d");
$datestop=$_POST['datestop'];
//echo "$today<br /><br />$datestop<br /><br />";
$begin = new DateTime("$today");
$end = new DateTime("$datestop");

<?php
  $sql="SELECT lng,lng_prefix FROM tbl_languages where active = 1";
  $result=mysqli_query($dbConn, $sql)or die(mysqli_error($dbConn)); //problem line
  if(mysqli_num_rows($result==1)){
      ?>