从javascript调用php并从php返回值到javascript

Question

I send a variable from js to php and in php i am running a query using the variable i got from js. After running the query i need to return the output of the query to js. I succeeded in sendind the variable and running the query.But unable to return the output.How can i return it?

Here is the code

JS

function abc () {
    var url = 'server/set_data.php';
    var paramstring = "vr=ViewLog&val=" + activityID1;
    ctype = "TEXT";
    AJAXRequest(url, paramstring, ctype, "VerifyData");
}

PHP

if(trim($_REQUEST[vr]) == 'ViewLog')
{
    if (trim($_REQUEST[val]) != "")
    {
        $sql="select abc from table where id='".$_REQUEST[val]."'";
        echo $sql;    
    }
}

Answer 1

Try this jQuery code, it will work

$.ajax({
    type   :"POST",
    data   :"vr=ViewLog&val="+activityID1,
    url    :'server/set_data.php', 
    success: function(msg){
        alert(msg); // here you can get the result from php page
     }
});

Answer 2

Are you sure, that the two conditional statements are executed the right way? I would set the array index in quotes:

if(trim($_REQUEST["vr"]) == 'ViewLog')
{
  if (trim($_REQUEST["val"]) != "")
  {
    $sql="select abc from table where id='".$_REQUEST[val]."'";
    echo $sql;   
  }
}

Additionally: You only return the SQL request string and not the result of a SQL request. Is this intended?