Today talked about three aspects
A determining
Two, three expressions
Third, circulation
Fourth, the function
details as follows:
1.if judgment
(1) if (condition) {
} When statement execution condition is satisfied
if the constraint condition determination
if ( "undefined") {// conditions are converted into Boolean
the console.log ( "nengshuchu " )
}
2. a triplet of expressions (trinocular operation, ternary operator)
if a simplified version
grammar:
? 1 expression represented by Formula 2: 3 Expression;
/ conditions (Boolean)
to true when the expression 2 down
to false when walking Expression 3
var = 100 A;
A == 100 the console.log ( "Hello")? : console.log ( "bad");
3. Cycle
Within the conditions, repeat to execute a section of code
for，for in，foreach，forof，while，dowhile
for (Condition 1; Condition 2; Condition 3; {
Circulation of statements}
break; exit the loop
continue; this cycle out
for(var i=0;i<10;i++){
console.log(i);
When if (i == 5) {condition is satisfied when
break; just met, the cycle is ended
}
}
4. Functions
Function: the package code, the code is a set of
Like naming convention rules and variables: function name
Parameters: parameter (formal parameters), the type parameter may be limited, the number may not be limited
Function body: Code function is called when the execution of
return: the return value, if not written, undefined is returned
function function name (parameter 1, parameter 2 ...) {
Function body
} Return return value of the function