Django cms editor 3.0.3 and HTML attributes getting removed -

i using cms-editor 3.0.3 when editing page , tags "placeholder" , "onclick" parameter getting removed. have pasted following code:

<div class="form-group"><input class="form-control" id="phnno" name="user-req-phone" placeholder="please enter phone" type="text" /></div>  <div class="col-sm-12"><button class="btn btn-primary btn-block mt20 " onclick="trip(1)" style="width: 100px; float: left;" type="submit">submit</button></div> 

after saving code automatically convert this:

<div class="form-group"><input class="form-control" id="phnno" name="user-req-phone" type="text" /></div>    <div class="col-sm-12"><button class="btn btn-primary btn-block mt20 " style="width: 100px; float: left;" type="submit">submit</button></div> 

please provide me solution can resolve problem.