How do I get the total of pixels in an irregular selection

[greless]

hi friends；

   How do I get the total of pixels in an irregular selection？Thank you for any idea。

[r-bin · Accepted solution]

var total = 0;

for (var i = 0; i < activeDocument.histogram.length; i++)
    total += activeDocument.histogram[i];

alert(total);

[greless]

Oh, it works，thanks,