<code lang="JavaScript">

//Function to trim the space in the left side of the string
function ltrim ( s ){
  return s.replace( /^\s*/, "" );
}

//Function to trim the space in the right side of the string
function rtrim ( s ){
   return s.replace( /\s*$/, "" );
}

//*Function to trim the space in the  string
function trim(s) {
   var temp = s;
   return temp.replace(/^\s+/,'').replace(/\s+$/,'');
}



</code>
ltrim() will remove all the spaces to the left in a string
rtrim() will remove all the spaces to the right in a string
trim() will all the left , right and spaces inside the string

Ex: 
var x = "  thestring"; 
ltrim(x) will return "thestring";

var y = "thestring  ";
rtrim(y) will return "thestring";

var z = " the st ri ng  ";
trim(z) will return "thestring"