Unable to send '+' through AJAX post?

I am using Ajax POST method to send data, but i am not able to send '+'(operator to the server i.e if i want to send 1+ or 20k+ it will only send 1 or 20k..just wipe out '+') HTML code goes here..

<form method='post' onsubmit='return false;' action='#'>
  <input type='input' name='salary' id='salary' />
  <input type='submit' onclick='submitVal();' />
</form>

and javascript code goes here,

function submitVal()
{
     var sal=document.getElementById("salary").value;
     alert(sal);
     var request=getHttpRequest();
     request.open('post','updateSal.php',false);
     request.setRequestHeader("Content-Type","application/x-www-form-urlencoded");
     request.send("sal="+sal);

     if(request.readyState == 4)
     {
        alert("update");
     }
}

           function getHttpRequest()
           {
               var request=false;
               if(window.XMLHttpRequest)
               {
                   request=new XMLHttpRequest();
               }
               else if(window.ActiveXObject)
               {
                   try
                   {
                       request=new ActiveXObject("Msxml2.XMLHTTP");
                   }
                   catch(e)
                   {
                       try
    开发者_开发知识库                   {
                           request=new ActiveXObject("Microsoft.XMLHTTP");
                       }
                       catch(e)
                       {
                           request=false;
                       }
                   }
               }

               return request;
           }

in the function submitVal() it first alert's the salary value as it is(if 1+ then alerts 1+), but when it is posted it just post's value without '+' operator which is needed... is it any problem with query string, as the PHP backend code is working fine...

Use

request.send("sal="+encodeURIComponent(sal));

The + is interpreted as an space on the server side so you need to encode the string first.

More info here:

http://xkr.us/articles/javascript/encode-compare/

You need to encode sal in request.send("sal="+sal). You'll probably find that if sal was equal to "foo & bar", you would end up with just "foo" on the server since the & needs to be encoded too. So:

request.send("sal=" + encodeURIComponent(sal)); // updated example

However, rather than doing this all by hand, you should think about using a library to do it for you, such as jQuery, then your example would look something like this:

$.ajax({
   url: "updateSal.php",
   type: "POST",
   data: { sal : $("salary").val() },
   success: function(){
      alert("update");
   }
});