通过JS监听input输入框的值来判断手机号

           <input
            name="name"
            type="text"
            class="dianhua ipt"
            autocomplete="off"
            placeholder="请输入您的电话号码"
            onfocus="this.placeholder=''"
            onblur="this.placeholder='请输入您的电话号码'"
            value=""
            oninput="getValue();"
            onporpertychange="getValue();"
              /> 

            <span class="baocuo" style="color: red;"></span>

// 手机号验证
var ipt = document.querySelector('.ipt')
var spans = document.querySelector('.baocuo')
var dh = false
function getValue() {
  // 获取input输入框的值
  var value = ipt.value
  // 输出值
  if (!/^1[34578]\d{9}$/.test(value)) {
    spans.innerHTML = '请输入正确的电话号码'
    spans.style.color = 'red'
  } else {
    spans.innerHTML = ''
    dh = true
  }
}