The return method is often used in functions, and its usage is also classic.
In the following sections, I will pay attention to the usage of return:
Usage 1: return function value:
Example 1: compile a compute class function:
Function JC (n ){
VaR j = 1;
For (VAR I = 0; I <= N; I ++ ){
J * = I;
}
Return J;
}
Alert (JC (5 ));
Calculate 5 here !, The output is 120;
Here, the return function is the value of the return function;
Example 2: Compile another compute class function:
Function JC (n ){
VaR j = 1;
For (VAR I = 0 ;;){
J * = ++ I;
If (I = N) {return J ;}
}
}
Alert (JC (5 ));
Calculate 5 here !, The output is 120;
Here, the return function is to jump out of the loop and jump out of the function. In the return function value;
Example 3: Another return example
Function CS (n ){
If (n = 1) {retrun 1 ;}
If (n = 2) {return ;}
Else {}
}
Note: When the parameter is 1, the function returns 1 and jumps out of the function,
When the parameter is 2, the function return value is null and jumps out of the function,
When the function is another value, continue to execute the following statements of the function until the next return or all statements are executed.
The preceding example shows that return can return the value of a function and jump out of the function;
The above example only describes the general purpose of return. Next, I will pay attention to it;
Return can return many data types. So far, I have not found that he cannot return anything.
This includes operations on the Dom, for example, or an example;
Example 4:
<Body>
<Div id = "KK"> AA </div>
</Body>
<SCRIPT>
Function CS (IDS ){
Return document. getelementbyid (IDS). firstchild. nodevalue;
}
Alert (CS ("KK "));
// The value in the DIV is aa;
Alert (document. getelementbyid (kk). firstchildnodevalue );
// Although the returned Div value is also AA;
But they are different. Do you know why ???
For example:
Document. getelementbyid (IDS). firstchild. nodevalue = "BB ";
In this case, the value in the DIV will be changed from AA to BB;
Everyone knows this,
When Cs ("KK") = "BB ";
Would you change the value in the DIV from AA to BB?
Here, you will understand that the objects returned by return cannot be assigned values;
That is to say, CS ("KK") = "BB"; errors will occur when assigning values in this way,
Here is what I want to talk about. Pay attention to the return !!!
More questions to be studied ......
</SCRIPT>
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