如何使用javascript验证用户输入（字符和数字）？

Question

From this example I tried to validate user input when a button was clicked.

$("#check_data").click(function () {
    var $userInput = $('#user_input'); //from HTML input box id="user_input"
    var pattern = " /*My user input always be like "AB1234567"*/ ";
    if ($userInput.val() == '' || !pattern.test($userInput.val())) {
        alert('Please enter a valid code.');
        return false;
    }
});

My user input input always be like "AB1234567" with this exact same characters but different 7 digits number. I'm new to Javascript and Jquery, if you have any better way to validate user input, please suggest it.

Thank you.

Answer 1

You can use below regex Expression to check

/[A-Za-z0-9]/g

Your code could be like this

    var _pattern=/[A-Za-z0-9]/g
    if($userInput.val().match(_pattern))
    {
        //your code goes here..
    }

Thanks

Answer 2

You can use the below pattern to check

/^AB\d{7}$/

You can change code to

var pattern = '/^AB\d{7}$/';
  if ($userInput.val() == '' || !pattern.test($userInput.val()))
  {
     alert('Please enter a valid code.');
     return false;
  }

\\d{7} matches 7 digits in the range [0-9]

Answer 3

You can follow below code for this:

if ($userInput.val().match(/[^a-zA-Z0-9 ]/g))
{
    // it is a valid value.

} else {
    // show error here
}

Hope it helps you.

Answer 4

Try this one.

$("#check_data").click(function(){
  var $userInput = $('#user_input').val();
  var pattern = /^AB[0-9]{7}?/g;
  if(!$userInput.match(pattern)){
      alert('Please enter a valid code.');
      return false;
  }
});