[Deff]

<script type="text/javascript">
var arr = [[1,2,3,4,5], 
           [5,0,7,8,0], 
           [5,6,7,8,1],  
           [8,9,9,9,12]];

function Replacer(i,j) {
   for(var J in arr[i]){
      arr[i][J]=0;
   }
   for(var I in arr){
      arr[I][j]=0;
   }
}


TST_arr0=[];

for(var i in arr){

   for(var j in arr[i]){

      if(arr[i][j]==0){
	  TST_arr0.push([i,j]);
      }
   }

}

for(var i in TST_arr0){
  Replacer(TST_arr0[i][0],TST_arr0[i][1])
}

</script>


<script>
// Print
 var str=''
for(var i in arr){
    str+='['+arr[i].join(",")+']\n'
}
alert(str);
</script>