1.jQuery 1.9.1 parseJSON: function( data ) { // Attempt to parse using the native JSON parser first if ( window.JSON && window.JSON.parse ) { return window.JSON.parse( data ); } if ( data === null ) { return data; } if ( typeof data === "stri
position的代码比较简单... position: function() { if ( !this[ 0 ] ) { return; } var offsetParent, offset, elem = this[ 0 ], parentOffset = { top: 0, left: 0 }; // Fixed elements are offset from window (parentOffset = {top:0, left: 0}, because it is its only