how to check if input field is empty

Question

I m making a form with inputs  if the input type is empty then the button submit is disabled but  if the input fields is with length   0 the submit button is enabled   lt input type  text  id  spa  onkeyup  check    gt  lt br gt   lt input type  text  id  eng  onkeyup  check    gt  lt br gt   lt input type  button  id  submit  disabled gt   function check       if     spa   lenght gt 0  amp  amp      eng   lenght gt 0            submit   prop  disabled   false       else           submit   prop  disabled   true           it works but if then I delete for example the content of input spa the button submit is still enabled

User · Answer

if you are using jquery-validate js in your application then use below expression   if     spa   is   blank          code

User · Answer

Why don t u use    lt script gt     input   keyup function    if      eng   val   length  gt  0   amp  amp       spa   val   length  gt  0           submit   prop  disabled   false   else         submit   prop  disabled   true        lt  script gt    Then delete the onkeyup function on the input

User · Answer

This snippet will handle more than two checkboxes in case you decide to expand the form      input type text    keyup function        var count   0  attr    disabled    sub       submit     inputs      input type text            inputs each function            count       trim   this  val       1 0               count  gt    inputs length      sub removeAttr attr   sub attr attr attr                Working Example  http   jsfiddle net sr4gq

User · Answer

use  val    it will return the value of the  lt input gt       spa   val   length  gt  0   And  you had a typo  length not lenght

User · Answer

Use trim and val     var value   trim     spa   val      if value length gt 0       do some stuffs       val     return the value of the input    trim    will trim the white spaces

User · Answer

Try this    trim     spa   val    length  gt  0   It will not treat any white space if any as a correct value

User · Answer

As javascript is dynamically typed  rather than using the  length property as above you can simply treat the input value as a boolean   var input     trim     spa   val      if  input           Do Stuff     You can also extract the logic out into functions  then by assigning a class and using the each   method the code is more dynamic if  for example  in the future you wanted to add another input you wouldn t need to change any code    So rather than hard coding the function call into the input markup  you can give the inputs a class  in this example it s test  and use       test   each function            this  keyup function                  submit   prop  disabled   CheckInputs                   which would then call the following and return a boolean value to assign to the disabled property   function CheckInputs         var valid   false          test   each function              if  valid    return valid            valid      trim   this  val                 return valid      You can see a working example of everything I ve mentioned in this JSFiddle

[jquery] how to check if input field is empty

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