Thread: Java Click button not working

Here is my coding, which I want to input first name and last name and then press the Save button. but when press the save button, seems the coding is not working and take effective. Can anyone suggest what's wrong on my coding? Or any suggestion? Thanks.

Program Coding :

<div class="form-r">
<label> First Name :</label><input type="text" id="first">
</div>

<div class="form-r">
<label> Last Name :</label><input type="text" id="last">
</div>

<div class="form-r">
<button id="butn"> Save</button>
</div>

<script>
Logger.log('before press butn');
document.getElementById("butn").addEventListenser( "click",dosumthing);

function dosumthing(){
Logger.log('press butn');
document.getElementById("first").value="";
document.getElementById("last").value="";
// var userInfo={};
// userInfo.firstname=document.getElementById("first" ).value;
// userInfo.lastname=document.getElementById("last"). value;
// google.script.run.userClicked(userInfo);
}