js implicitly on a different type of operation

1. strings and numbers are added, converted into a digital string.

var one="This is a test";
var two=123;
var three=one+two;

// result: three: This is a test123

2. The digital values ​​are added and Boolean, Boolean false turn into 0, true turn into a

var one=13;
var two=true;
var three=one+two;
// 结果 three:14

3. String Boolean value is added, the Boolean value into a string.

var one=‘hello ’;
var two=true;
var three=one+two;
// 结果 hello true

4. Digital and the null (empty value) are added, null into a digital 0:

var CAR = null + +. 4. 3;     // result 7

The string and the null (empty value) are added, null string is converted to:

var CAR = null + "A";     // results nulla

6. The result of the modulo operation with only the left sign symbol values ​​for:

var X =. 7%. 3; // results. 1 
var Y =. 7% (-3); // results. 1 
var Z = (-7)%. 3; // results -1

•  % If left operand is positive, then the result of addition to the mold for positive or zero;
•  % If left operand is negative, the result of the modulo negative or zero.

 

Summarized as follows:

1, can be a very powerful string data type; performed plus  +, the object will be added to a string unitary.

2, bool type when added to the digital type, regarded as 0 or 1 process.

3, when the null type and digital type accumulates 0 considered treatment.

4, the null type bool type accumulates deemed to sum and processing integer type.

5, undefined except effective (undefined as a character string "undefined" process), otherwise returns are accumulated during string NaN.

6, modulo  % computations, the computation result depends only on the sign of the first number.