jQuery check if input exists and has a value

Question

I have the following example    lt input type  text  class  input1  value  bla   gt    Is there a way to check if this element exists and has a value in one statement  Or  at least  anything shorter then  if     input1   length  gt  0  amp  amp     input1   val            Just getting frustrated here with mile-long conditions

User · Answer

You can do something like this   jQuery fn existsWithValue   function          return this length  amp  amp  this val   length      if    selector  existsWithValue                 Do something

User · Answer

You can create your own custom selector  hasValue and then use that to find  filter  or test any other jQuery elements   jQuery expr      hasValue   function el index match      return el value             Then you can find elements like this   var data      form input hasValue   serialize      Or test the current element with  is    var elHasValue       name   is   hasValue       x000D   x000D  jQuery expr      hasValue   function el    x000D    return el value        x000D     x000D   x000D   x000D  var data      form input hasValue   serialize    x000D  console log data  x000D   x000D   x000D  var elHasValue       name  LastName     is   hasValue    x000D  console log elHasValue  x000D  label   display  block  margin-top 10px    x000D   lt script src  https   ajax googleapis com ajax libs jquery 2 1 1 jquery min js  gt  lt  script gt  x000D   x000D   lt form gt  x000D     lt label gt  x000D      First Name  x000D       lt input type  text  name  FirstName  value  Frida    gt  x000D     lt  label gt  x000D   x000D     lt label gt  x000D      Last Name  x000D       lt input type  text  name  LastName    gt  x000D     lt  label gt  x000D   lt  form gt  x000D   x000D   x000D    Further Reading    Make jQuery  contains Case-Insensitive Make Your Own Custom jQuery Selector Exploring jQuery Selectors  Part 3

User · Answer

Just for the heck of it  I tracked this down in the jQuery code  The  val   function currently starts at line 165 of attributes js  Here s the relevant section  with my annotations   val  function  value         var hooks  ret  isFunction          elem   this 0                NO ARGUMENTS  BECAUSE NOT SETTING VALUE     if    arguments length                  IF NOT DEFINED  THIS BLOCK IS NOT ENTERED  HENCE  UNDEFINED          if   elem                 hooks   jQuery valHooks  elem type      jQuery valHooks  elem nodeName toLowerCase                   if   hooks  amp  amp   get  in hooks  amp  amp   ret   hooks get  elem   value         undefined                     return ret                             ret   elem value                   IF IS DEFINED  JQUERY WILL CHECK TYPE AND RETURN APPROPRIATE  EMPTY  VALUE             return typeof ret      string                       handle most common string cases                 ret replace rreturn                           handle cases where value is null undef or number                 ret    null        ret                     return          So  you ll either get undefined or    or null -- all of which evaluate as false in if statements

User · Answer

The input won t have a value if it doesn t exist  Try this     if     input1   val

User · Answer

I would do something like this     input value    something   This finds all inputs that have value and operates something onto them

User · Answer

You could do   if     input1   length  amp  amp      input1   val   length    length evaluates to false in a condition  when the value is 0

User · Answer

if     user inp   length  gt  0  amp  amp      user inp   val                     user inp   css   font-size   18px             user line   css   background-color    4cae4c   transition   0 5s   height   2px             username   css   color    4cae4c   transition   0 5s   font-size   18px

[javascript] jQuery check if <input> exists and has a value

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