jQuery checking if the value of a field is null empty

Question

Is this a good way to check if the value of a field is null   if     person data document type    value       NULL       Or is there a better way

User · Accepted Answer

The value of a field can not be null  it s always a string value   The code will check if the string value is the string  NULL   You want to check if it s an empty string instead   if      person data document type    val              or   if      person data document type    val   length    0      If you want to check if the element exist at all  you should do that before calling val   var  d       person data document type     if   d length    0      if   d val   length    0

User · Answer

jquery provides val   function and not value    You can check empty string using jquery  if     person data document type    val

User · Answer

that depends on what kind of information are you passing to the conditional    sometimes your result will be null or undefined or    or 0  for my simple validation i use this if         id   val       0         id   val                id   val       undefined         id   val      null     NOTE  null     null

User · Answer

Try   x000D   x000D  if  this  person data document type    value           x000D    console log  not empty    x000D    x000D   lt input id  person data document type   value  test    gt  x000D   x000D   x000D

User · Answer

helpers              Check is string null or empty         isStringNullOrEmpty  function  val                switch  val                    case                     case 0                  case  0                   case null                  case false                  case undefined                  case typeof this      undefined                       return true                  default  return false                                      Check is string null or whitespace         isStringNullOrWhiteSpace  function  val                return this isStringNullOrEmpty val     val replace   s g                                    If string is null or empty then return Null or else original value         nullIfStringNullOrEmpty  function  val                if  this isStringNullOrEmpty val                     return null                            return val                     Utilize this helpers to achieve that

User · Answer

I would also trim the input field  cause a space could make it look like filled  if    trim     person data document type    val

User · Answer

Assuming  var val       person data document type    value      you have these cases   val      NULL       actual value is a string with content  NULL  val                 actual value is an empty string val     null        actual value is null  absence of any value    So  use what you need

User · Answer

My Working solution is var town code       town code   val      if town code trim   length    0       var town code   0

[javascript] jQuery: checking if the value of a field is null (empty)

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