Detect when input has a readonly attribute

Question

I want to throw an alert when an input has a  readonly  attribute  I have tried this     if    input   attr  readonly       readonly         alert  foo          I think that  if  is not even the best way to do it

User · Answer

try this   if    input   attr  readonly      undefined       alert  foo        if it is not there it will be undefined in js

User · Answer

Try a simple way   if    input readonly  readonly          alert  foo

User · Answer

Check the current value of your  readonly  attribute  if it s  false   a string  or empty  undefined or     then it s not readonly      input   each function         var readonly     this  attr  readonly        if readonly  amp  amp  readonly toLowerCase      false        this is readonly         alert  this is a read only field

User · Answer

fastest way is to use the  is   jQuery function   if      input   is   readonly            using  readonly  as a selector simply checks if the attribute is defined on your element  if you want to check for a value  you can use something like this instead   if      input   is   readonly  somevalue

User · Answer

You can just use the attribute selector and then test the length      input readonly    length    0    -- gt  ok    input readonly    length  gt  0     -- gt  not ok

User · Answer

what about javascript without jQuery    for any input that you can get with or without jQuery  just    input readOnly   note   mind camelCase

User · Answer

In vanilla pure javascript you can check as following -   var field   document querySelector  input name  fieldName      if field readOnly    alert  foo

User · Answer

Since JQuery 1 6  always use  prop   Read why here  http   api jquery com prop   if    input   prop  readonly          prop   can also be used to set the property     input   prop  readonly  true       input   prop  readonly  false

[jquery] Detect when input has a 'readonly' attribute

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