JAVA AJAX C++

jQuery.extend = jQuery.fn.extend = function() {
 // copy reference to target object
 var target = arguments[0] || {}, a = 1, al = arguments.length, deep = false;

 // Handle a deep copy situation

//這個IF條件基本上總是false,只有當target對象是布爾類型時才會是真,也就是這段代碼好像沒有什么作用

  if ( target.constructor == Boolean ) {  
  deep = target;
  target = arguments[1] || {};
 }

 // extend jQuery itself if only one argument is passed
 if ( al == 1 ) {
  target = this;
  a = 0;
 }

 var prop;

 for ( ; a < al; a++ )
  // Only deal with non-null/undefined values
  if ( (prop = arguments[a]) != null )
   // Extend the base object
   for ( var i in prop ) {
    // Prevent never-ending loop
    這一段代碼不知道怎么搞的，說是用來阻止死循環(huán)，但我怎么也不明白他是如何阻止的，好像卻了他也沒什么影響。
    if ( target == prop[i] )
     continue;

    // Recurse if we're merging object values
    if ( deep && typeof prop[i] == 'object' && target[i] )
     jQuery.extend( target[i], prop[i] );

    // Don't bring in undefined values
    else if ( prop[i] != undefined )
     target[i] = prop[i];
   }

 // Return the modified object
 return target;
};