Javascript (1)--Import file and basic syntax

1. Importing files

2. Variable type

Except for underscores, any special symbols outside the dollar sign are not allowed, and true is the keyword

3. Type conversion

The "+" number refers to the string connection, not the next addition, so d=103

Result: The first interception of digital =67

Second: Rounding not rounding =53

Third: Convert the binary to a decimal =12

Fourth one: =nan (meaning not a number)

The second: string to float is not automatically converted, so the latter is considered to be a string, discarding

Fourth: Two decimal points, take the first one

4. Common operation

Javascript (1)--Import file and basic syntax