输入字段不能为空

Question

我有一个输入字段，除非您输入/选择某些内容，否则该字段不允许您搜索。我该怎么做呢？

<input type="text" class="form-control pg-csr-customer-search CSRinputBut" aria-label="" id="CustomerSearchText" name="CustomerSearchText" value="" placeholder="Search Customer" required>

当用户点击或点击进入时，我需要显示此警告。

displayCustomerSearchMessage('<i class=\"fa fa-exclamation-circle pull-left\"></i> Sorry, missing selected Customer Id. Please make a selection from the results listing.', 'warning');

Answer 1

<input type="text" name="CustomerSearchText" id="CustomerSearchText" onblur="checkTextField(this);" />


//modify following code as your need
function checkTextField(field) {
    if (field.value == '') {
        alert("empty!!!");
    }
}

<强>更新

<form onsubmit="return checkTextField(this)">


function checkTextField(form) {
  var text = form.CustomerSearchText.value;

    if (text == '') {
            return false
        }


  return true;
}