JavaScript实用知识库分享

return new XMLHttpRequest();

ActiveXObject } else if(typeof != 'undefined') {

arguments callee activeXString if(typeof . . !=

'string') { // activeXString

versions = ["MSXML2.XMLHttp", "MSXML

2.XMLHttp.3.0", "MSXML2.XMLHttp.6.0"];

i len versions lengthfor(var = 0, = . ;

i len i < ; ++) {

try {

xhr var = new Active

}

}

arguments calreturn newActiveXObect( .

lee activeXString. );

} else {

throw new Error("No XHR object

available.");

}

}

}

script type< ="text/javascript">

XMLHttpRequest if(typeof != 'undefined') {

createXHR = function() {

versions = ["MSXML2.XMLHttp",

"MSXML2.XMLHttp.3.0", "MSXML2.XMLHttp.6.0"];

i len for(var = 0, =

versions length i len i . ; < ; ++) {

try {

xhr var = new

versions iActiveXObject( [ ]);

arguments ca.

llee activeXString versions i. = [ ];

xhrreturn ;

lee activeXString. );

};

} else {

createXHR = function() {

throw new Error("No XHR object

available.");

};

}

return createXHR();

}

start var = new Date().getTime();

n var fibonacci = function( ) {

n n n n return < 2 ? : fibonacci( - 1) + fibonacci( - 2);

}

document.write(fibonacci(30));

end var = new Date().getTime();

console end start .log("" + ( - ) + ""); //31

memo var = [0, 1];

n var fib = function( ) {

result memo nvar = [ ];

result if(typeof !== 'number') { //

result n n= fib( - 1) + fib( -2);

memo n result[ ] = ;

}

result return ; //

};

fibreturn ;