得到了一个输入字段，有一个最大长度为6，当键入正常工作正常，但当我尝试使用我做的键盘，它没有。它似乎只是绕过限制，如果它甚至不存在。
超文本：

<div class="bank-screen">
  <h1>Please enter your pin to continue</h1>
  <div class="options">
    <input name="pin" oninput="javascript: if (this.value.length > this.maxLength) this.value = this.value.slice(0, this.maxLength);"
    type = "number"
    maxlength = "4"
    id="pinfield">
  </div>
  <div class="keypad">
    <div class="keys">   
    <button value="1" class="key" onclick="GetNum(this)">1</button>
    <button value="2" class="key" onclick="GetNum(this)">2</button>
    <button value="3" class="key" onclick="GetNum(this)">3</button>
    <button value="4" class="key" onclick="GetNum(this)">4</button>
    <button value="5" class="key" onclick="GetNum(this)">5</button>
    <button value="6" class="key" onclick="GetNum(this)">6</button>
    <button value="7" class="key" onclick="GetNum(this)">7</button>
    <button value="8" class="key" onclick="GetNum(this)">8</button>
    <button value="9" class="key" onclick="GetNum(this)">9</button>
    <button class="key"></button>
    <button value="0" class="key" onclick="GetNum(this)">0</button>
    <button class="key"></button>
    <button class="key" id="submit">Submit</button>
    <button class="key" id="cancel">Cancel</button>
    <button class="key" id="clear" onclick="clearall()">Clear</button>
  </div>
</div>

联森：

function GetNum(a){
var pinfield = document.getElementById("pinfield");
pinfield.value = pinfield.value + a.value;

}

function clearall(){
var pinfield = document.getElementById("pinfield");
pinfield.value = null;

}

var result = 103/50;
result = Math.floor(result);

console.log(result);