How to get the caret column not pixels position in a textarea in characters from the start

Question

How do you get the caret position in a  lt textarea gt  using JavaScript   For example  This is  a text  This should return 7   How would you get it to return the strings surrounding the cursor   selection   E g    This is         a text    If the word    is    is highlighted  then it would return  This     is     a text

User · Accepted Answer

With Firefox  Safari  and other Gecko based browsers  you can easily use textarea selectionStart  but for IE that doesn t work  so you will have to do something like this   function getCaret node      if  node selectionStart        return node selectionStart      else if   document selection        return 0         var c     001         sel   document selection createRange          dul   sel duplicate          len   0     dul moveToElementText node     sel text   c    len   dul text indexOf c     sel moveStart  character  -1     sel text         return len       complete code here   I also recommend you to check the jQuery FieldSelection Plugin  it allows you to do that and much more     Edit  I actually re-implemented the above code    function getCaret el       if  el selectionStart         return el selectionStart       else if  document selection         el focus          var r   document selection createRange         if  r    null           return 0               var re   el createTextRange             rc   re duplicate         re moveToBookmark r getBookmark          rc setEndPoint  EndToStart   re         return rc text length           return 0       Check an example here

User · Answer

If you don t have to support IE  you can use selectionStart and selectionEnd attributes of textarea   To get caret position just use selectionStart   function getCaretPosition textarea      return textarea selectionStart     To get the strings surrounding the selection  use following code   function getSurroundingSelection textarea      return  textarea value substring 0  textarea selectionStart            textarea value substring textarea selectionStart  textarea selectionEnd            textarea value substring textarea selectionEnd  textarea value length       Demo on JSFiddle   See also HTMLTextAreaElement docs

User · Answer

Updated 5 September 2010  Seeing as everyone seems to get directed here for this issue  I m adding my answer to a similar question  which contains the same code as this answer but with full background for those who are interested   IE  39 s document selection createRange doesn  39 t include leading or trailing blank lines  To account for trailing line breaks is tricky in IE  and I haven t seen any solution that does this correctly  including any other answers to this question  It is possible  however  using the following function  which will return you the start and end of the selection  which are the same in the case of a caret  within a  lt textarea gt  or text  lt input gt    Note that the textarea must have focus for this function to work properly in IE  If in doubt  call the textarea s focus   method first   function getInputSelection el        var start   0  end   0  normalizedValue  range          textInputRange  len  endRange       if  typeof el selectionStart     number   amp  amp  typeof el selectionEnd     number             start   el selectionStart          end   el selectionEnd        else           range   document selection createRange             if  range  amp  amp  range parentElement      el                len   el value length              normalizedValue   el value replace   r n g    n                    Create a working TextRange that lives only in the input             textInputRange   el createTextRange                textInputRange moveToBookmark range getBookmark                     Check if the start and end of the selection are at the very end                of the input  since moveStart moveEnd doesn t return what we want                in those cases             endRange   el createTextRange                endRange collapse false                if  textInputRange compareEndPoints  StartToEnd   endRange   gt  -1                    start   end   len                else                   start   -textInputRange moveStart  character   -len                   start    normalizedValue slice 0  start  split   n   length - 1                   if  textInputRange compareEndPoints  EndToEnd   endRange   gt  -1                        end   len                    else                       end   -textInputRange moveEnd  character   -len                       end    normalizedValue slice 0  end  split   n   length - 1                                                       return           start  start          end  end

User · Answer

Updated 5 September 2010  Seeing as everyone seems to get directed here for this issue  I m adding my answer to a similar question  which contains the same code as this answer but with full background for those who are interested   IE  39 s document selection createRange doesn  39 t include leading or trailing blank lines  To account for trailing line breaks is tricky in IE  and I haven t seen any solution that does this correctly  including any other answers to this question  It is possible  however  using the following function  which will return you the start and end of the selection  which are the same in the case of a caret  within a  lt textarea gt  or text  lt input gt    Note that the textarea must have focus for this function to work properly in IE  If in doubt  call the textarea s focus   method first   function getInputSelection el        var start   0  end   0  normalizedValue  range          textInputRange  len  endRange       if  typeof el selectionStart     number   amp  amp  typeof el selectionEnd     number             start   el selectionStart          end   el selectionEnd        else           range   document selection createRange             if  range  amp  amp  range parentElement      el                len   el value length              normalizedValue   el value replace   r n g    n                    Create a working TextRange that lives only in the input             textInputRange   el createTextRange                textInputRange moveToBookmark range getBookmark                     Check if the start and end of the selection are at the very end                of the input  since moveStart moveEnd doesn t return what we want                in those cases             endRange   el createTextRange                endRange collapse false                if  textInputRange compareEndPoints  StartToEnd   endRange   gt  -1                    start   end   len                else                   start   -textInputRange moveStart  character   -len                   start    normalizedValue slice 0  start  split   n   length - 1                   if  textInputRange compareEndPoints  EndToEnd   endRange   gt  -1                        end   len                    else                       end   -textInputRange moveEnd  character   -len                       end    normalizedValue slice 0  end  split   n   length - 1                                                       return           start  start          end  end

User · Answer

I modified the above function to account for carriage returns in IE  It s untested but I did something similar with it in my code so it should be workable   function getCaret el      if  el selectionStart         return el selectionStart       else if  document selection         el focus          var r   document selection createRange         if  r    null           return 0               var re   el createTextRange         rc   re duplicate         re moveToBookmark r getBookmark          rc setEndPoint  EndToStart   re         var add newlines   0      for  var i 0  i lt rc text length  i            if  rc text substr i  2       r n             add newlines    2          i                         return rc text length   add newlines         We need to substract the no  of lines     return rc text length - add newlines           return 0

User · Answer

If you don t have to support IE  you can use selectionStart and selectionEnd attributes of textarea   To get caret position just use selectionStart   function getCaretPosition textarea      return textarea selectionStart     To get the strings surrounding the selection  use following code   function getSurroundingSelection textarea      return  textarea value substring 0  textarea selectionStart            textarea value substring textarea selectionStart  textarea selectionEnd            textarea value substring textarea selectionEnd  textarea value length       Demo on JSFiddle   See also HTMLTextAreaElement docs

User · Answer

I modified the above function to account for carriage returns in IE  It s untested but I did something similar with it in my code so it should be workable   function getCaret el      if  el selectionStart         return el selectionStart       else if  document selection         el focus          var r   document selection createRange         if  r    null           return 0               var re   el createTextRange         rc   re duplicate         re moveToBookmark r getBookmark          rc setEndPoint  EndToStart   re         var add newlines   0      for  var i 0  i lt rc text length  i            if  rc text substr i  2       r n             add newlines    2          i                         return rc text length   add newlines         We need to substract the no  of lines     return rc text length - add newlines           return 0

[javascript] How to get the caret column (not pixels) position in a textarea, in characters, from the start?

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