jQuery hasAttr checking to see if there is an attribute on an element

Question

How do you check if there is an attribute on an element in jQuery  Similar to hasClass  but with attr   For example    if    this  hasAttr  name

User · Answer

Object prototype hasAttr   function attr        if this attr            var  attr   this attr attr         else           var  attr   this getAttribute attr             return  typeof  attr      undefined   amp  amp   attr     false  amp  amp   attr     null              I came a crossed this while writing my own function to do the same thing    I though I d share in case someone else stumbles here   I added null because getAttribute   will return null if the attribute does not exist    This method will allow you to check jQuery objects and regular javascript objects

User · Answer

How about just   this  is   name      The  attr  syntax is the CSS selector for an element with an attribute attr  and  is   checks if the element it is called on matches the given CSS selector

User · Answer

You can also use it with attributes such as disabled  disabled  on the form fields etc  like so       change password   click function         var target     this  attr  rel        if         target  attr  disabled                      target  attr  disabled   false         else                   target  attr  disabled   true               The  rel  attribute stores the id of the target input field

User · Answer

The best way to do this would be with filter        nav gt ul gt li gt a   filter   data-page-id       It would still be nice to have  hasAttr    but as it doesn t exist there is this way

User · Answer

I wrote a hasAttr   plugin for jquery that will do all of this very simply  exactly as the OP has requested  More information here  EDIT  My plugin was deleted in the great plugins jquery com database deletion disaster of 2010  You can look here for some info on adding it yourself  and why it hasn t been added

User · Answer

If you will be checking the existence of attributes frequently  I would suggest creating a hasAttr function  to use as you hypothesized in your question     fn hasAttr   function name         return this attr name      undefined        document  ready function         if     edit   hasAttr  id              alert  true          else           alert  false                lt div class  edit  id  div 1  gt Test field lt  div gt

User · Answer

Late to the party  but    why not just this hasAttribute  quot name quot    Refer This

User · Answer

var attr     this  attr  name        For some browsers   attr  is undefined  for others      attr  is false   Check for both  if  typeof attr     typeof undefined  amp  amp  attr     false

User · Answer

You re so close it s crazy   if   this  attr  name      There s no hasAttr but hitting an attribute by name will just return undefined if it doesn t exist   This is why the below works  If you remove the name attribute from  heading the second alert will fire    Update  As per the comments  the below will ONLY work if the attribute is present AND is set to something not if the attribute is there but empty   lt script type  text javascript  gt    document  ready function         if      heading   attr  name          alert  Look  this is showing because it  s not undefined        else       alert  This would be called if it were undefined or is there but empty         lt  script gt   lt h1 id  heading  name  bob  gt Welcome  lt  h1 gt

[jquery] jQuery hasAttr checking to see if there is an attribute on an element

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