White zero-based front-end Web can learn it? How to learn JS? Web front-end entry is relatively simple, many applications, the preferred language is a zero-based learning IT development. However, after the completion of HTML + CSS learning, many students will be stumped --JS JS syntax, data types JS, JS effect three elements: time, events and sports such as track and miscellaneous knowledge points, we want to master the very difficult Big. But as long as you put the knowledge comb clear, true understanding and use of them, you can master it. Here we give the type of data to share knowledge about the JS.
Why do we want to grasp the type of data it? Because master data types can reasonably allocate memory, optimize resources, reduce storage space. In JS There are six common data types: Undefined, Null, Boolean (Boolean), string (String), value (Number), the object (Object).
1、Undefined
Undefined only one type of value undefined. Typeof operator will execute on an uninitialized variable and undeclared returns undefined.
2、Null
Null data type is the second type is only one value, i.e. null. A null value indicates a null pointer to an object, the flow returns "object" null value detected typeof operator.
3, Boolean type
It has two values: true and false, but it should be noted that not necessarily equal to true 1, false not necessarily equal to 0. And the process of writing to be case sensitive, True or False Boolean value is not just an identifier only. In JavaScript can be converted to a boolean value by calling the function transformation of Boolean ().
4, String type
String can be represented by a single quote ( ') or double quotes ( ") to indicate a sequence of zero or more characters 16, i.e. a string of Unicode characters.
5, Number type
JavaScript is only one digital type. Numbers with decimal points can also be without.
6, Object data type
Also known as the object, is a collection of data and functions (function). You can use the name of the object type followed by the new operator to create to create. Create method can also be expressed by literal. They were added at different attributes (the empty string comprises an arbitrary strings).
In addition, ES6 introduces a new type of raw data Symbol, represent a unique value, which is the seventh data types JavaScript language. JS is a literal scripting language widely used client, it is a kind of dynamic typing, weak and prototype-based language, the main role is to increase the dynamic HTML pages function, business recruitment interview process is more emphasis on problem, so you have to master JS.
For no experience of "zero-based" students, the self-study Web front-end development is relatively not so easy. So choose a professional learning is very important to be able to grasp the leading edge of technology development faster, learning will be more effective.