document.onmouseup = function(){ this.onmousemove = null; this.onmouseup = null; } ,這里的this指向()
A.window對象 B.document對象 C.function對象 D.以上說法都正確
A.Object B.Error C.Function D.loading
var a=2; var func=(function(){ var a=3; return function(){ a++; alert(a) } })() alert分別輸出什么值?()
A.3,4 B.4,4 C.4,5 D.undefined,undefined