防止聚合物纸张输入退格

Question

I have a polymer input field like this:

<paper-input type="text" class="user-value" data-id="user-value" value="{{typingAns}}" focus maxlength="10" />

is it possible to block the backspace functionality on this input? Basically, if the user press backspace is it possible to keep typingAns the same? I tried to use onkeydown but it doesn't seem to work.

Thanks a lot.

Answer 1

I actually fix this with:

preventBackspace : function preventBackspace(){
  window.addEventListener("keydown", function(e){
    if(e.keyCode === 8) {
    e.preventDefault();
    console.log('Prevent page from going back');
    }
  });
}

and

typingAnsChanged: function() {
      var _this = this;
      if (this.typingAns) {
        _this.preventBackspace();
      }
    }