PHP returns value with 1-2 second delay jQuery.post doesn't wait for response.

How do you think, is it possible to fix that problem and wait for response?

    $.post( sSource, aoData, function (data) {    

        oCache.lastJson = jQuery.extend(true, {}, data);

        if ( oCache.iCacheLower != oCache.iDisplayStart )

        {

            data.aaData.splice( 0, oCache.iDisplayStart-oCache.iCacheLower );

        }

        data.aaData.splice( oCache.iDisplayLength, data.aaData.length );

         abc(oCache);

        fnCallback(data); 

    },json );

Note the same function with get works well

    $.getJSON( sSource, aoData, function (json) { 

        /* Callback processing */

        oCache.lastJson = jQuery.extend(true, {}, json);



        if ( oCache.iCacheLower != oCache.iDisplayStart )

        {

            json.aaData.splice( 0, oCache.iDisplayStart-oCache.iCacheLower );

        }

        json.aaData.splice( oCache.iDisplayLength, json.aaData.length );



        fnCallback(json)

    } );