面向面试准备、在线测试、教程与实战练习的学习平台

通过聚焦学习路径、模拟测试和面试实战内容持续提升技能。

WithoutBook 将分主题面试题、在线练习测试、教程和对比指南整合到一个响应式学习空间中。

搜索资源库

面试准备

JavaScript 面试题与答案

Test your skills through the online practice test: JavaScript Quiz Online Practice Test

问题 26. Explain String functions in Javascript.

a class defines a new type (formally, Abstract Data Type)
encapsulates data (properties) and operations on that data (methods)

a String encapsulates a sequence of characters, enclosed in quotes

properties include
length : stores the number of characters in the string

methods include
charAt(index) : returns the character stored at the given index
(as in C++/Java, indices start at 0)
substring(start, end) : returns the part of the string between the start
(inclusive) and end (exclusive) indices
toUpperCase() : returns copy of string with letters uppercase
toLowerCase() : returns copy of string with letters lowercase

to create a string, assign using new or just make a direct assignment (new is implicit)

word = new String("foo"); word = "foo";

properties/methods are called exactly as in C++/Java

word.length word.charAt(0)

这有帮助吗？是否添加评论查看评论

问题 27. Tell us about local variables.

If needed, you can declare local variables within a function.

local variable is visible only within the function body after it’s declared.

Commonly used to store results of an intermediate calculation.

function findMaxValue(num1, num2,num3) {
var tempMax; //local var

if (num1 >= num2) {
tempMax = num1;
}

else {
tempMax = num2;
}

if(num3 >= tempMax) {
tempMax = num3;
}

return tempMax;

} //end function

这有帮助吗？是否添加评论查看评论

问题 28. Explain Global Variables in Javascript.

Global variables are those declared outside of functions
Global variables are ‘visible’ from anywhere in the program, including inside functions

var globalHello = “Hello!”;

function writeHello() {
document.write(globalHello);
}
// outputs “Hello!”

这有帮助吗？是否添加评论查看评论

问题 29. What are primitives in Javascript?

Boolean, string and number.

这有帮助吗？是否添加评论查看评论

问题 30. How do you submit a form using Javascript?

Use document.forms[0].submit();
(0 refers to the index of the form – if you have more than one form in a page, then the first one has the index 0, second has index 1 and so on).

这有帮助吗？是否添加评论查看评论

1
2
3
4
5
6
7
8
9
10
11
12

用户评价最有帮助的内容：

JavaScript vs Jquery	JavaScript vs VBScript	JavaScript vs TypeScript

通过聚焦学习路径、模拟测试和面试实战内容持续提升技能。

JavaScript 面试题与答案

相关差异对比

问题 26. Explain String functions in Javascript.

问题 27. Tell us about local variables.

问题 28. Explain Global Variables in Javascript.

问题 29. What are primitives in Javascript?

问题 30. How do you submit a form using Javascript?

WithoutBook