关于操作元素的class属性，正确的是： A: A，element.setAttribute('className', 'active'); B: B，element.class = 'active'; C: C，element.className = 'active'; D: D，element.class-name = 'active';

以下哪项是类实例化的语句?( )。 A: varName ClassName=new varName() B: ClassName varName=new ClassName(new ClassName) C: ClassName varName=ClassName() D: ClassName varName=new ClassName()

下列无效的CSS选择器的是( ) A: className a B: className .a C: a.className a D: a.className .a E: span[data-type=1] F: className:first-child G: div:before

A DC servo-motor is a type of ( ) applied to automatic control systems A: actuator B: amplifying element C: correcting element D: measuring element

If A is a matrix, the function max(A(:)) is ( ). A: to return the first element B: to return the maximum element in each row of the matrix C: to return the maximum element in each column of the matrix D: to return the largest element of the entire matrix

CSS中让元素隐藏，但是不清除元素的方法是（ ） A: element { display: none; } B: element { display: block;} C: element { visibility: visible; } D: element { visibility: hidden; }

In a singly linked list which operation depends on the length of the list.( ) A: Interchange the first two elements of the list B: Delete the first element of the list C: Add an element before the first element of the list D: Delete the last element of the list

two-terminal element

The quality element is ______ .

element distance