Get cookie values

[ABorrello]

Hi,
I am new to javascript and I am trying to develop a way to filter cookies on my site.
As the user interacts with some of my site elements, I need certain cookies to change. I simply need a way to filter through my cookie list (document.cookie) to find a specific cookie name. I have this so far...

function valueget() {
var findinstr = document.cookie;
var tofindstr = document.getElementById('tofind').value;
var findresult = '';
var str_parts = findinstr.split(";");
var i = 0;
while (findresult==''||i<=str_parts.length-1) {
if (str_parts[i].substring('','=')==tofindstr) {
findresult = str_parts[i].substring('=','');
}
else {
i = i + 1;
}
}
if (findresult=='') {
alert('Could not be found');
}
else {
alert(findresult);
}
}

and the HTML code is simply

<input type="text" id="tofind">
<input type="button" value="Get Value" onclick="valueget()">

Is this the best way to find a cookie name and value, or is there an easier way.

By the way, every time I test this script, my page freezes

Any help is appreciated

[Logic Ali]

Originally Posted by ABorrello

Is this the best way to find a cookie name and value, or is there an easier way.

By the way, every time I test this script, my page freezes

If you want to search, this topic has been covered zillions of times, although not always very well...

The essential problem is your misuse of substring, which expects to work with integer parameters, not strings.

The statement

if (str_parts[i].substring('','=')==tofindstr)

could be something like

if( str_parts[i].substring( 0, str_parts[i].indexOf( '=' ) ) == tofindstr )

although it is important to split on "; " not ";".

Here is an example of using the String.split approach and also a RegEx example:

function readCookie( cName ) /* Uses String.split */
{
  var pairs = ( document.cookie || "" ).split( "; " ), 
      len = pairs.length, 
      offset;  
   
  for( var i = 0; i < len && ( offset = pairs[ i ].indexOf( cName + '=' ) ) != 0; i++ )
  ;
 
  return  i != len ? decodeURIComponent( pairs[ i ].substring( offset + cName.length + 1 ) ) : "" ;   
}


function readCookie( cName ) /* Uses Regex */
{
  var v;

  return decodeURIComponent( ( v = ( document.cookie || "" ).match( "(^|\\s)" + cName + "=([^;$]+)" ) ) ? v[ 2 ] : "" );
}