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【单选题】
Which of the following statements about variable declare in js is correct? ( )
A.
The var keyword cannot be omitted when js defines a variable, otherwise an error will be reported.
B.
Variable name cannot start with $.
C.
The declaration of a variable is represented by the keyword var, but it can also be omitted.
D.
Js variables are declared by var just like php variables.
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【多选题】(Multiple-choice question) Which of the following statements about obtaining page elements are correct? ( )
A.
document.getElementById("a") means to obtain an element in the page by the id value "a".
B.
document.getElementsByName("na")means to obtain an element in the page by the name attribute value "na".
C.
document.getElementsByTagName("div") means to get all divs by tag name.
D.
The above statements are not correct.
【单选题】What does the following code output? ( )var i=0, j=0; for(; i<10, j<7; i++, j++) { k=i+j; }console.log(k);
A.
16
B.
10
C.
12
D.
6
【单选题】Run the following code, y and z result are ( ) respectively.var m=1,j=k=0;function add(n){return n=n+1;}y=add(m);function add(n){return n=n+3;}z=add(m);
A.
2,4
B.
4,4
C.
2,2
D.
exception
【单选题】Which of the following expressions returns false? ( )
A.
!(3<=1)
B.
(4>=4) && (5<=2)
C.
("a"=="a") && ("c" != "d")
D.
(2<3) || (3<2)
【单选题】Which of the following ways to introduce external js into html is corrent? ( )
A.
<script href='https://cdn.shuashuati.com/imgs/a95092819215d41e0a25bd3c08990fa0tion'></script>
B.
<script src='https://cdn.shuashuati.com/imgs/a95092819215d41e0a25bd3c08990fa0tion'></script>
C.
<script link='https://cdn.shuashuati.com/imgs/a95092819215d41e0a25bd3c08990fa0tion'></script>
D.
<script target='https://cdn.shuashuati.com/imgs/a95092819215d41e0a25bd3c08990fa0tion'></script>
【单选题】Which of the following statements about JavaScript function is correct? ( )
A.
Parameters are acceptable.
B.
There is no difference between arguments and formal parameters.
C.
There is no return type.
D.
There is noreturn keyword.
【单选题】下列哪一项正向事件描述符合青春期阶段?
A.
发展出对不同任务的胜任感
B.
发展出对下一代的关爱,关心他们的健康和发展
C.
学会无私奉献和得到回报
D.
探索自我认同的各个方面,形成整合的自我概念