function lTrim(sStr){

     while (sStr.charAt(0) == " ")

      sStr = sStr.substr(1, sStr.length - 1);

     return sStr;

    }

 

    function rTrim(sStr){

     while (sStr.charAt(sStr.length - 1) == " ")

      sStr = sStr.substr(0, sStr.length - 1);

     return sStr;

    }

 

    function allTrim(sStr){

     return rTrim(lTrim(sStr));

    }

 

    function prueba(){

     with (document.frm){

      original.value = ">" + usuario.value + "<";

      lTrimmed.value = ">" + lTrim(usuario.value) + "<";

      rTrimmed.value = ">" + rTrim(usuario.value) + "<";

      allTrimmed.value = ">" + allTrim(usuario.value) + "<";

     }

    }