Q:

if size == 4,7,10,13, .... so on... in jQuery

I know i can do like this...
if (Size == 4 | Size == 7 | Size == 10 | Size == 13 | Size == 16 | Size == 19)
{alert("Yes!")} 

But any better coding ? 

A:

if(Size%3==1&&Size<20&&Size>3 )
{alert("yes");}

A:

You can use jQuery.inArray :
if (jQuery.inArray(Size, [4, 7, 10, 13, 16, 19])>=0) {

Note that the goal can only be readability, not performances. 
If you have only those 6 values and if they never change, the ugly if you made (with || instead of |) is a perfectly correct solution. 

A:

switch (Size) {
    case 4:
    case 7:
    case 10:
    case 13:
    case 16:
    case 19:
        alert("Yes!"); 
}

