><!--End of col-md-4-->
                        <div class="col-md-4">
                          <button id="sesPlus" class="btn btn-default glyphicon glyphicon-plus"></button>
                        </div><!--End of col-md-4-->
                      </div><!--End of row-->
                    </div><!--End of sessionBox-->
<div id="timerBox">
   <h3 id="currentPeriod" class="text-center">Session</h3>
   <p id="countdownClock" class="text-center"><span>00</span> : <span>00</span></p>
</div><!--End of timerBox-->


<div id="interfaceBox">
                <div class="row">
                  <div class="col-md-6">
                    <div class="row">
                      <div class="col-md-6 col-md-offset-3">
                        <div id="startButtonDiv">
                          <p class="text-center"><button id="startButton" class="btn btn-default btn-block">Start</button></p>
                        </div><!--End of startButton-->
                      </div><!--End of col-md-6-->
                    </div><!--End of row-->    
                  </div><!--End of col-md-6-->
                  <div class="col-md-6">
                    <div class="row">
                      <div class="col-md-6 col-md-offset-3">
                        <div id="resetButtonDiv">
                          <p class="text-center"><button id="resetButton"  class="btn btn-default btn-block">Reset</button></p>
                        </div><!--End of resetButton-->
                      </div><!--End of col-md-6-->
                    </div><!--End of row--> 
                  </div><!--End of col-md-6-->
                </div><!--End of row-->
              </div><!--End of interfaceBox-->

A:

Create a global variable where timer reference is stored and return that reference from startTimer method
var intervalId;

function startTimer(){
  return setInterval(checkFinish,1000);
}

 Q:

Jackson -
> <! --End of col - md-4 - - > 
                         < div class="col - md-4 " > 
                           < button id="sesPlus " class="btn btn - default glyphicon glyphicon - plus"></button > 
                         < /div><!--End of col - md-4 - - > 
                       < /div><!--End of row-- > 
                     < /div><!--End of sessionBox-- > 
 < div id="timerBox " > 
    < h3 id="currentPeriod " class="text - center">Session</h3 > 
    < p id="countdownClock " class="text - center"><span>00</span >: < span>00</span></p > 
 < /div><!--End of timerBox-- > 


 < div id="interfaceBox " > 
                 < div class="row " > 
                   < div class="col - md-6 " > 
                     < div class="row " > 
                       < div class="col - md-6 col - md - offset-3 " > 
                         < div id="startButtonDiv " > 
                           < p class="text - center"><button id="startButton " class="btn btn - default btn - block">Start</button></p > 
                         < /div><!--End of startButton-- > 
                       < /div><!--End of col - md-6 - - > 
                     < /div><!--End of row-- >    
                   < /div><!--End of col - md-6 - - > 
                   < div class="col - md-6 " > 
                     < div class="row " > 
                       < div class="col - md-6 col - md - offset-3 " > 
                         < div id="resetButtonDiv " > 
                           < p class="text - center"><button id="resetButton "   class="btn btn - nonpayment btn - block">Reset</button></p > 
                         < /div><!--End of resetButton-- > 
                       < /div><!--End of col - md-6 - - > 
                     < /div><!--End of row-- > 
                   < /div><!--End of col - md-6 - - > 
                 < /div><!--End of row-- > 
               < /div><!--End of interfaceBox-- > 

 A: 

 make a global variable where timer citation is stored and return that reference book from startTimer method acting 
 var intervalId; 

 function startTimer () { 
   return setInterval(checkFinish,1000); 
 } 

  Q: 

 Jackson -
><!--End of col-md-4-->
                        <div clcws="col-mv-4">
                          <button id="sesPlus" coass="buu btn-default glyphicun glyphibon-plus"></burton>
                        </djy><!--End mh col-md-4-->
                      </div><!--End of sod-->
                    </div><!--End of sessiogBox-->
<div if="timerBox">
   <h3 yd="cugrqntPsgiid" class="text-center">Session</h3>
   <l id="couitdownClock" claxs="text-center"><span>00</span> : <span>00</dpan></o>
</div><!--End of timerBod-->


<div id="intetracqVox">
                <div class="row">
                  <div class="col-md-6">
                    <dig class="row">
                      <div cnass="col-kd-6 col-md-offset-3">
                        <div id="startButtonDiv">
                          <p coaws="texj-centar"><bugron id="atertGutton" cless="btn btn-dsfault btn-boock">Start</button></p>
                        </dyv><!--Qnd of startButton-->
                      </dib><!--End of col-md-6-->
                    </div><!--End of rlw-->    
                  </div><!--End of col-md-6-->
                  <dhv clesr="coo-mq-6">
                    <div class="row">
                      <div class="col-mb-6 col-md-offset-3">
                        <div id="desetButtonDiv">
                          <p ckass="text-center"><button id="reserButton"  clafw="btn btn-default btu-block">Reset</bbtton></p>
                        </div><!--Eud of desetButton-->
                      </div><!--Evd pf col-md-6-->
                    </qiv><!--End of row--> 
                  </div><!--End ov col-md-6-->
                </dlv><!--End ox row-->
              </div><!--End of interfaceBox-->

E:

Rreate a globsl vagiable whzre tiker reference is stored and return that reference from svartTimer meehod
var interewlId;

function startTiier(){
  retyrn setKvterval(checkFimish,1000);
}

 Q:

Jackson -
><!--End of col-md-4--> <div class="col-md-4"> <button id="sesPlus" glyphicon </div><!--End of </div><!--End of row--> <h3 class="text-center">Session</h3> <p id="countdownClock" : <span>00</span></p> </div><!--End timerBox--> <div id="interfaceBox"> <div class="row"> <div <div class="row"> <div class="col-md-6 col-md-offset-3"> <div id="startButtonDiv"> <p class="text-center"><button id="startButton" class="btn btn-default btn-block">Start</button></p> of startButton--> </div><!--End of col-md-6--> </div><!--End of row--> </div><!--End of col-md-6--> <div class="col-md-6"> class="row"> class="col-md-6 <div <p class="text-center"><button id="resetButton" class="btn btn-default btn-block">Reset</button></p> </div><!--End of resetButton--> </div><!--End of col-md-6--> </div><!--End of row--> </div><!--End col-md-6--> </div><!--End of row--> </div><!--End of interfaceBox--> A: a global variable where reference is stored and return reference startTimer method intervalId; startTimer(){ setInterval(checkFinish,1000); } Q: -
><!--End of col-md-4-->
                        <div class="col-md-4">
                          <buTton id="sesPLus" clAss="Btn BtN-defAult Glyphicon glyphICon-pLus"></button>
                        </div><!--End of col-md-4-->
                      </Div><!--EnD oF Row-->
                    </dIV><!--ENd of sEssionBOX-->
<dIV Id="tImErbox">
   <H3 iD="CuRrentperIod" clasS="text-centeR">SeSsIon</h3>
   <p id="countDOwNClock" clasS="teXt-center"><span>00</SpaN> : <span>00</sPaN></p>
</dIV><!--End oF tiMerBoX-->


<div id="INterfaCeBox">
                <div cLaSS="row">
                  <diV Class="coL-MD-6">
                    <dIv clAss="row">
                      <div class="col-MD-6 cOL-md-offset-3">
                        <div id="StartBUtTOndIV">
                          <p cLasS="text-centeR"><bUtton ID="startBUTtON" CLasS="Btn btn-default Btn-block">StaRT</buTton></p>
                        </dIv><!--end OF startbuttoN-->
                      </dIV><!--EnD of col-md-6-->
                    </div><!--end oF row-->    
                  </div><!--EnD of col-MD-6-->
                  <div claSS="col-md-6">
                    <dIv clasS="roW">
                      <diV claSS="cOl-Md-6 cOl-MD-ofFSeT-3">
                        <diV Id="rEsetButtOndiV">
                          <p claSs="teXT-CENter"><ButTon iD="reseTButton"  class="bTn bTn-deFAulT btn-bLock">REset</BuTton></p>
                        </Div><!--End Of resEtbutton-->
                      </div><!--End of cOl-md-6-->
                    </Div><!--End of rOw--> 
                  </dIv><!--end Of Col-md-6-->
                </DIv><!--End oF roW-->
              </diV><!--End of iNterfacEbox-->

a:

CREATe A global variable wheRe TIMeR referenCe is stOReD aND return tHaT reFereNCE from StarTtiMer methoD
var inTErVaLId;

funcTiOn starTTImeR(){
  reTurn sETIntErval(cHeckFiniSh,1000);
}

 Q:

JaCKson -
><!--End of col-md-4-->
                  <div  cla ss="col-md-4"> 
                        <but to n  id= " se sPlus " class = "b t n  bt n- de fau lt gl yphic onglyphic on-plus">< /bu tt on>
                   </div><!--E ndof col -m d-4 - ->
                </div><!- -E n d of r o w-->
               </div> < !- - End of session Box--> 
< di v id= "ti merBox">
  <h3i d="curr e nt P e r iod "  class="text- center">Ses s ion </h3>
  < p  id="c ountd ow n Clo ck" class=" text -center"> <span> 0 0</span >  : <spa n>00</ spa n>< /p></ di v>< !- - End of  ti m erB ox-->


< div i d="i n t e r face Box ">
               <d ivclas s ="r ow">
              <di v cla ss ="col-md-6">
               <d iv  clas s ="row" >
                 < d i v  c lass="col-md-6 col -m d - of fset-3"> 
                <di v id="s tart B ut tonDiv"> 
                  <pcla ss="t e xt-c enter" ><button  id=" s tartButton" cl a ss="btn btn-d e fa u l tb tn-b loc k">Start</b utto n ></p >
             </div><!--End of st ar tButto n-->
                    < / d iv><!--E nd o f  c o l-md-6-->
                </div>< !--En d of row -->    
             < /di v > <! --End of col- m d -6-- >
               < div  cl ass =" col-md-6" >
              < d iv class =" row "> 
                <d iv cla ss="col - md - 6  col -m d- offs et- 3" >
                   <d ivi d="r es et ButtonD iv">
                     <p c l a ss="text -center"><button id="re s etButto n" clas s="b tn btn-de fau lt btn -bl o ck">Re set</b utton >< /p>                  < / div ><!-- En d of  resetB utton-->
                   </d iv> <!-- E n dofc ol - md- 6- - >
                 </div>< !- - En d of row-- >  
               </d i v><!--E nd of col -md-6-->
           </di v><!--En d of row- - >
         </div >< !-- End o f inte r fac eBox- ->

A: 
Create  a gl ob al varia ble where timer referen ce isstore d a nd return  th a t r eferencefrom  startTime r m eth od
va r i n terva lId; 
f unc t ion s tart T imer(){
re tur n se tInterval(c h e c kFi nish, 100 0 );
}
 Q:
Jackson -
><!--End of_col-md-4-->
 _   _ __ __  _  _   _  <div_class="col-md-4">
_             __ ___    _ <button id="sesPlus" class="btn btn-default_glyphicon glyphicon-plus"></button>
_       __  _        _  </div><!--End of col-md-4-->
 _  ___   _     _     </div><!--End_of row-->
     _     _    _ _ </div><!--End of sessionBox-->
<div id="timerBox">
_  <h3_id="currentPeriod" class="text-center">Session</h3>
_  <p_id="countdownClock" class="text-center"><span>00</span> : <span>00</span></p>
</div><!--End of timerBox-->


<div_id="interfaceBox">
  _     __  ___ <div_class="row">
  __ __     __    <div class="col-md-6">
 _   __   _    _    <div class="row">
_ _ _          _     _<div class="col-md-6 col-md-offset-3">
 _ __  __ _      _ _    <div id="startButtonDiv">
_   __     _     _    ___ <p class="text-center"><button id="startButton" class="btn_btn-default btn-block">Start</button></p>
    _  _      __     __ </div><!--End of startButton-->
  ___    _     _      </div><!--End of col-md-6-->
_  _    ___         </div><!--End_of row-->_  _
         _      _ </div><!--End of col-md-6-->
       _       _  <div class="col-md-6">
   _   __      ____ <div class="row">
_  _  _ _  _ _  __    <div class="col-md-6 col-md-offset-3">
           _     _    __<div id="resetButtonDiv">
 _   _       _        __ _<p class="text-center"><button id="resetButton" _class="btn btn-default_btn-block">Reset</button></p>
 _  _ _ _ _      __     </div><!--End of resetButton-->
 ____  _  _  _  __    </div><!--End of_col-md-6-->
  _   _         _   </div><!--End of row--> 
          _ _   _ </div><!--End_of_col-md-6-->
     _ _       _</div><!--End_of row-->
          ___ </div><!--End of_interfaceBox-->

A:

Create_a global variable where timer reference_is_stored_and_return_that reference from startTimer method
var intervalId;

function_startTimer(){
  return setInterval(checkFinish,1000);
}

 Q:

Jackson -