isset in jQuery

Question

Possible Duplicate    Finding whether the element exists in whole html page       i would like make somethings   HTML    lt span id  one  gt one lt  span gt   lt span id  two  gt two lt  span gt   lt span id  three  gt three lt  span gt    JavaScript   if  isset     one         alert  yes       if  isset     two         alert  yes       if  isset     three         alert  yes       if   isset     four         alert  no        LIVE   http   jsfiddle net 8KYxe   how can I make that

User · Answer

php js   http   www phpjs org    has a isset   function  http   phpjs org functions isset 454

User · Answer

if       one   length  gt  0       alert  yes       if       two   length  gt  0       alert  yes       if       three   length  gt  0       alert  yes       if       four    length    0      alert  no        This is what you need

User · Answer

function isset element        return element length  gt  0      http   jsfiddle net 8KYxe 1     Or  as a jQuery extension     fn exists   function     return this length  gt  0         later     if       id   exists            do something

User · Answer

You can simply use this   if      one        alert  yes       if      two        alert  yes       if      three        alert  yes       if      four        alert  no        Sorry  my mistake  it does not work

User · Answer

You can use length   if     one   length       0    false   gt 0    true     alert  yes

User · Answer

function el id      return document getElementById id      if  el  one      el  two      el  three         alert  yes       else if  el  four        alert  no

[php] isset in jQuery?

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