css - When I click on my HTML button, a blue "selection" border is displayed -

this question has answer here:

• remove blue border css custom-styled button in chrome 12 answers

i created html button, , after styling css, every time it's clicked blue selection border appears around it. there way fix this? know default unchanged element not when create it, i'm thinking must have css added.

html:

<button type="button" class="drop-button" >-</button> 

css:

.drop-button {     background-color: #343436;     color: #ffffff;     border: none;     border-radius: 5px;     margin-right: 8px;     margin-left: 4px;     height: 20px;     width: 25px;     font-size: 20px;     vertical-align: middle;     line-height: 0px; } 

here link it. http://jsfiddle.net/xytxnpyt/

this default behavior of chrome. can turn off this...

button:focus{ outline: none; }