i want to display all checkboxes value which are checked

I want to display all checked checkboxes in php.

<script>
    function RequestObject () 
    {
        var ReturnValue = null;
        try { 
            ReturnValue = new ActiveXObject("Microsoft.XMLHTTP"); 
        }
        catch (Error) {
            try { 
                ReturnValue = new ActiveXObject("MSXML2.HTTP"); 
            }
            catch (Error) {
                try { 
                    ReturnValue = new XMLHttpRequest(); 
                }
                catch (Error) { 
                    // failed 
                    return null;
                }
            }
        }
        return ReturnValue;
    }
    var requestObj = null;        
    function coajax(sender)
    {
        requestObj = RequestObject();
        if (requestObj)
        {
            sender.enabled = false; // so a user cannot change till request finished
            requestObj.open('get', '<?php echo get_template_directory_uri(); ?>/lunch_dinner.php?lid=' + sender.value, true);
            requestObj.onreadystatechange = coajax_finish;
            requestObj.send(null);
        }
    }
    function coajax_finish()
    {
        if (requestObj.readyState == 4)
        {
            document.getElementById('ldb_target').innerHTML = requestObj.responseText;
            document.getElementById('ldb').enabled = true;
        }
    }
    function getDays(select){
        var selectedString = select.options[select.selectedIndex].value;
        if(selectedString == "Bespoke Days"){
            document.getElementById("days_target").style.display = "block"; 
        }
        else { 
            document.getElementById("days_target").style.display = "none"; 
        }
    }
    function validateForm()
    {
        var x=document.forms["form1"]["contract"].value;
        if (x==null || x=="" || x=="Select Contract")
        {
            alert("Oh, you forgot to select contract type! :)");
            return false;
        }
        var x=document.forms["form1"]["days"].selectedIndex;
        if (x<1) 
        {
            alert("Please select days");
            return false;
        }
        else if(x==4) { // fifth entry 
            var checked = false, 
            chk = document.forms["form1"]["day"];
            for (var i = 0; i < chk.length; i++) 
            {
                if (chk[i].checked) { checked=true; break }
            }
            if (!checked) {
                alert("At least one day should be checked.");
                return false;
            }
        }
        var x=document.forms["form1"]["ldb"].value;
        if (x==null || x=="" || x=="Select")
        {
            alert("Oh, you forgot to select lunch-dinner! :)");
            return false;
        }
        var x=document.forms["form1"]["ldb"].value;
        if(x=="Lunch" || x=="Both")
        {
            var y=document.forms["form1"]["lunch"].value;
            if(y=="Lunch")
            {
                alert("Oh, you forgot to select lunch time! :)");
                return false;
            }
        }
        var x=document.forms["form1"]["ldb"].value;
        if(x=="Dinner" || x=="Both")
        {
            var y=document.forms["form1"]["dinner"].value;
            if(y=="Dinner")
            {
                alert("Oh, you forgot to select dinner time! :)");
                return false;
            }
        }
        var x=document.forms["form1"]["phone"].value;
        if (x==null || x=="")
        {
            alert("Oh, you forgot to enter your Phone Number! :)");
            return false;
        }
        var x = document.form1.phone.value;
        if(isNaN(x)||x.indexOf(" ")!=-1)
        {
            alert("Please enter Numaric value in contact number.")
            return false;
        }
        var x=document.forms["form1"]["meal"].value;
        if (x==null || x=="" || x=="Select Meal")
        {
            alert("Oh, you forgot to select meal preference! :)");
            return false;
        }
        var x=document.forms["form1"]["fnm"].value;
        if (x==null || x=="")
        {
            alert("Oh, you forgot to enter your Full Name! :)");
            return false;
        }
        var x=document.forms["form1"]["pcod"].value;
        if (x==null || x=="")
        {
            alert("Oh, you forgot to enter your Postal Code! :)");
            return false;
        }
        var x=document.forms["form1"]["email"].value;
        if (x==null || x=="")
        {
            alert("Oh, you forgot to enter your Email Address! :)");
            return false;
        }
        var x=document.forms["form1"]["email"].value;
        var atpos=x.indexOf("@");
        var dotpos=x.lastIndexOf(".");
        if (atpos<1 || dotpos<atpos+2 || dotpos+2>=x.length)
        {
            alert("Excuse me! Valid Email Address Please!");
            return false;
        }
        var x=document.forms["form1"]["add"].value;
        if (x==null || x=="")
        {
            alert("Oh, you forgot to enter your Address! :)");
            return false;
        }
        var x=document.forms["form1"]["rate"].value;
        if (x==null || x=="")
        {
            alert("Oh, you forgot to enter Rate! :)");
            return false;
        }
        var x=document.forms["form1"]["rate"].value;
        if(isNaN(x)||x.indexOf(" ")!=-1)
        {
            alert("Please enter Numaric value in Rate.")
            return false;
        }
        var x=document.forms["form1"]["amount"].value;
        if (x==null || x=="")
        {
            alert("Oh, you forgot to enter Amount! :)");
            return false;
        }
        var x=document.forms["form1"]["amount"].value;
        if(isNaN(x)||x.indexOf(" ")!=-1)
        {
            alert("Please enter Numaric value in Total Amount.")
            return false;
        }
    }
    function calculateTotal(rate)
    {
        var rate=(document.forms["form1"]["rate"].value) * 1.03;
        document.forms["form1"]["amount"].value = rate;
    }
</script>

HTML:

<form method="POST" action="" name="form1" onsubmit="return validateForm();">
    <table class="order-paypal" width="100%">
        <tr>
            <td><span>Choose contract</span></td>
            <td>
                <select name="contract">
                    <option value="Select Contract" selected>Select Contract</option>
                    <option value="7 meal veg contract">7 meal veg contract</option>
                    <option value="7 meal nonveg contract">7 meal nonveg contract</option>
                    <option value="7 meal nonveg contract">7 meal nonveg contract</option>
                    <option value="8 meal veg contract">8 meal veg contract</option>
                    <option value="8 meal nonveg contract">8 meal nonveg contract</option>
                    <option value="8 meal mix contract">8 meal mix contract</option>
                    <option value="9 meal veg contract">9 meal veg contract</option>
                    <option value="9 meal nonveg contract ">9 meal nonveg contract  </option>
                    <option value="9 meal mix contract ">9 meal mix contract  </option>
                    <option value="30 meal veg contract">30 meal veg contract</option>
                    <option value="30 meal nonveg contract">30 meal nonveg contract</option>
                    <option value="30 meal mix contract">30 meal mix contract</option>
                    <option value="Book-a-cook service">Book-a-cook service</option>
                    <option value="Extra roti/rice/dal/vegetable">Extra roti/rice/dal/vegetable</option>
                </select>
            </td>
        </tr>
        <tr>
            <td><span>Please enter days required</span></td>
            <td>
                <select name="days" id="days" onchange="getDays(this)">
                    <option value="Select Days" selected>Select Days</option>
                    <option value="Mon-Fri">Mon-Fri</option>
                    <option value="Mon-Sat">Mon-Sat</option>
                    <option value="Mon-Sun">Mon-Sun</option>
                    <option value="Bespoke Days">Bespoke Days</option>
                </select>

                <ul id="days_target" style="display:none;">
                    <span>Select Days</span>
                    <li><input type="checkbox" name="day[]" value="mon"/>Monday</li>
                    <li><input type="checkbox" name="day[]" value="tue"/>Tueday</li>
                    <li><input type="checkbox" name="day[]" value="wed"/>Wednesday</li>
                    <li><input type="checkbox" name="day[]" value="thr"/>Thursday</li>
                    <li><input type="checkbox" name="day[]" value="fri"/>Friday</li>
                    <li><input type="checkbox" name="day[]" value="sat"/>Saturday</li>
                    <li><input type="checkbox" name="day[]" value="sun"/>Sunday</li>
                </ul>
            </td>
        </tr>       
        <tr>
            <td><span>Please mention Lunch or Dinner or both</span></td>
            <td>
                <select name="ldb" id="ldb" onchange="coajax(this);" >
                    <option value="Select" selected>Select</option>
                    <option value="Lunch">Lunch</option>
                    <option value="Dinner">Dinner</option>
                    <option value="Both">Both</option>
                </select>
                <span id="ldb_target"></span><br/>
            </td>
        </tr>
        <tr>
            <td><span>Please mention your contact number</span></td>
            <td><input type="text" name="phone" /></td>
        </tr>   
        <tr>
            <td><span>Please mention your meal preference</span></td>
            <td>
                <select name="meal" >
                    <option value="Select Meal" selected>Select Meal</option>
                    <option value="Punjabi">Punjabi</option>
                    <option value="Gujarati">Gujarati</option>
                </select>
            </td>
        </tr>
        <tr>
            <td style="vertical-align:top;"><span>Please mention any dietary requirements</span></td>
            <td><input type="text" name="req" ></td>
        </tr>   
        <tr>
            <td><span>Full name</span></td>
            <td><input type="text" name="fnm" ></td>
        </tr>
        <tr>
            <td><span>Address</span></td>
            <td><textarea name="add" ></textarea></td>
        </tr>       
        <tr>
            <td><span>Postal code</span></td>
            <td><input type="text" name="pcod" ></td>
        </tr>           
        <tr>
            <td><span>Email</span></td>
            <td><input type="text" name="email" ></td>
        </tr>               
        <tr>
            <td><span>Enter amount to pay</span></td>
            <td>
                <input type="text" name="rate" >
                <br />
                (<a target="_blank" href="http://www.infozzle.com/yatin/tifffin_planet/prices-and-offers-2/">Check the rate of your item and your zone</a>)
                <br/>
                Card charge: 3% of the total amount
            </td>
        </tr>
        <tr>
            <td><span>Total Amount</span></td>
            <td><input type="text" name="amount" value="Click here to see total amount" onclick="calculateTotal(this);"></td>
        </tr>
        <tr>
            <td>&nbsp;</td>
            <td>
                <table class="submit">
                    <tr>
                        <td><input type="submit" value="Submit" name="submitbtn" class="submit-payment"/></td>
                        <td><input type="reset" value="Reset" class="submit-reset"/></td>
                    </tr>
                </table>
            </td>
        </tr>
    </table>
</form>

I want to display all checked checkboxes of “day” on action page by this code:

<?php 
    foreach($day as $k)
    { 
        echo $k.","; 
    }
?>

html Form and action page are in template page of wordpress.
but it doesn’t work.how to do?i have written this code.