JavaScript comma-expression

The general form of a comma expression is: expression 1, expression 2, expression 3 ... Expression n
The solution to the comma expression is to evaluate the value of the expression 1, then the value of the expression 2, ... Always evaluates to the value of the expression N. The value of the last entire comma expression is the value of the expression N.
Look at the following examples:

 x=8*2,x*4 /*   Span style= "color: #008000;" >*/  (x  =8*2,x*4), x*2 /*   */  x  = (z=5,5 * *) /*   The entire expression is an assignment expression with a value of 10,z of 5  */  x  =z=5,5*2 /*   */ 

< Span style= "color: #454545; font-family:tahoma,helvetica,arial; font-size:14px; line-height:21px; " such as: printf ("%d,%d,%d", X, Y, z); The ########################################################### operator causes the expression on either side of it to be executed from left to right, and to get the value of the right-hand expression. , the most common purpose of an operator is to use it in an increment expression for a for loop. For example: &NBSP;

 for (i = 0; i < ten; i++, J + +) {    = i + j;}

each time the end of the loop is passed, the For statement allows only a single expression to be executed. , an operator is used to allow multiple expressions to be treated as a single expression, thereby circumventing the restriction.

JavaScript comma-expression