How to force a input field only accept integer?

intInput.js

/**
  * 强制输入框只能输入正整数
  * @param {string} id 输入框的id
*/
function intInput(id) {
  var item = document.querySelector(id);
  item.onkeyup = forceInt;
  item.onafterpaste = forceInt;

  function forceInt() {
    this.value = this.value.replace(/[^0-9]+/, '').replace(/^0+/, '');
  }
}