javascript - Looping through a table to store the position of a cell -

i have question regarding looping through table of data not storing data in table; instead, store location of piece of data in table.

what working table of pgm pixel values either defined number 0 black , 255 white. hoping table loop through , store location of pixel, row , column number, in array, if pixel displays value of 255.

i don't have pgm table me @ moment i'll provide 1 example. make simple please me log position of pixels display value of 15? answers appreciated :)

p2 # feep.pgm 24 7 15 0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0 0  3  3  3  3  0  0  7  7  7  7  0  0 11 11 11 11  0  0 15 15 15 15  0 0  3  0  0  0  0  0  7  0  0  0  0  0 11  0  0  0  0  0 15  0  0 15  0 0  3  3  3  0  0  0  7  7  7  0  0  0 11 11 11  0  0  0 15 15 15 15  0 0  3  0  0  0  0  0  7  0  0  0  0  0 11  0  0  0  0  0 15  0  0  0  0 0  3  0  0  0  0  0  7  7  7  7  0  0 11 11 11 11  0  0 15  0  0  0  0 0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0 

you can this:

var locs = [],     row,     col,     pixeldata = ...,     nrows = ...,     ncols = ...; (row = 0; row < nrows; ++row) {     (col = 0; col < ncols; ++col) {         if (pixeldata[row][col] == 15) {             locs.push([row, col]);         }     } } // locs array has [row,col] locations of pixels value 15 

in above, pixeldata array of rows, each of array of pixel values:

var pixeldata = [     [0,  0,  0,  0,  0,  0,  0,  0,  0,  . . .],     [0,  3,  3,  3,  3,  0,  0,  7,  7,  . . .],     . . . ]; 

at end, should expect locs array of two-element arrays, if initialized with:

var locs = [     [1, 19], [1,20], [1,21], [1,22], [2, 19], [2,22], ... ];