How do you check if a selector matches something in jQuery

Question

In Mootools  I d just run if     target              Does if      target            in jQuery work the same way

User · Answer

For me  exists doesn t work  so I use the index    if      elem   index       -1

User · Answer

Yet another way       elem   each function         do stuff

User · Answer

jQuery fn exists   function selector  callback        var  this     this        this each function             callback call this     this  find selector  length  gt  0

User · Answer

no  jquery always returns a jquery object regardless if a selector was matched or not  You need to use  length  if       someDiv   length

User · Answer

if you used   jQuery fn exists   function   return    this  length  gt  0    if    selector  exists          you would imply that chaining was possible when it is not   This would be better  jQuery exists   function selector   return    selector  length  gt  0    if    exists selector

User · Answer

no  jquery always returns a jquery object regardless if a selector was matched or not  You need to use  length  if       someDiv   length

User · Answer

Alternatively   if  jQuery   elem   get 0

User · Answer

if you used   jQuery fn exists   function   return    this  length  gt  0    if    selector  exists          you would imply that chaining was possible when it is not   This would be better  jQuery exists   function selector   return    selector  length  gt  0    if    exists selector

User · Answer

For me  exists doesn t work  so I use the index    if      elem   index       -1

User · Answer

As the other commenters are suggesting the most efficient way to do it seems to be    if    selector  length            Do something     If you absolutely must have an exists   function - which will be slower- you can do   jQuery fn exists   function   return this length gt 0     Then in your code you can use  if    selector  exists             Do something     As answered here

User · Answer

firstly create a function     fn is exists   function    return document getElementById selector      then  if   selector  is exists

User · Answer

I prefer the       if  jQuery   anyElement   is              Which basically checks if this elements is a kind of      any element   Just a cleaner syntax and the  is  makes more sense inside an  if

User · Answer

I think most of the people replying here didn t quite understand the question  or else I might be mistaken   The question is  how to check whether or not a selector exists in jQuery    Most people have taken this for  how to check whether an element exists in the DOM using jQuery   Hardly interchangeable   jQuery allows you to create custom selectors  but see here what happens when you try to use on e before initializing it       YEAH     Syntax error  unrecognized expression  YEAH    After running into this  I realized it was simply a matter of checking  if    expr       YEAH             Query for your  YEAH selector with ease of mind      Cheers

User · Answer

no  jquery always returns a jquery object regardless if a selector was matched or not  You need to use  length  if       someDiv   length

User · Answer

firstly create a function     fn is exists   function    return document getElementById selector      then  if   selector  is exists

User · Answer

Alternatively   if  jQuery   elem   get 0

User · Answer

Yet another way       elem   each function         do stuff

User · Answer

I think most of the people replying here didn t quite understand the question  or else I might be mistaken   The question is  how to check whether or not a selector exists in jQuery    Most people have taken this for  how to check whether an element exists in the DOM using jQuery   Hardly interchangeable   jQuery allows you to create custom selectors  but see here what happens when you try to use on e before initializing it       YEAH     Syntax error  unrecognized expression  YEAH    After running into this  I realized it was simply a matter of checking  if    expr       YEAH             Query for your  YEAH selector with ease of mind      Cheers

User · Answer

no  jquery always returns a jquery object regardless if a selector was matched or not  You need to use  length  if       someDiv   length

User · Answer

if you used   jQuery fn exists   function   return    this  length  gt  0    if    selector  exists          you would imply that chaining was possible when it is not   This would be better  jQuery exists   function selector   return    selector  length  gt  0    if    exists selector

User · Answer

Alternatively   if  jQuery   elem   get 0

User · Answer

I prefer the       if  jQuery   anyElement   is              Which basically checks if this elements is a kind of      any element   Just a cleaner syntax and the  is  makes more sense inside an  if

User · Answer

if      elem   0          do stuff

User · Answer

jQuery fn exists   function selector  callback        var  this     this        this each function             callback call this     this  find selector  length  gt  0

User · Answer

if you used   jQuery fn exists   function   return    this  length  gt  0    if    selector  exists          you would imply that chaining was possible when it is not   This would be better  jQuery exists   function selector   return    selector  length  gt  0    if    exists selector

User · Answer

As the other commenters are suggesting the most efficient way to do it seems to be    if    selector  length            Do something     If you absolutely must have an exists   function - which will be slower- you can do   jQuery fn exists   function   return this length gt 0     Then in your code you can use  if    selector  exists             Do something     As answered here

User · Answer

Alternatively   if  jQuery   elem   get 0

User · Answer

As the other commenters are suggesting the most efficient way to do it seems to be    if    selector  length            Do something     If you absolutely must have an exists   function - which will be slower- you can do   jQuery fn exists   function   return this length gt 0     Then in your code you can use  if    selector  exists             Do something     As answered here

User · Answer

if      elem   0          do stuff

User · Answer

As the other commenters are suggesting the most efficient way to do it seems to be    if    selector  length            Do something     If you absolutely must have an exists   function - which will be slower- you can do   jQuery fn exists   function   return this length gt 0     Then in your code you can use  if    selector  exists             Do something     As answered here

[javascript] How do you check if a selector matches something in jQuery?

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