Kaviar's web interface accepts input in a variety of ways. Please note that the form has three input fields: one for specifying a chromosome, one for specifying a single coordinate or range (or multiple coordinates/ranges), and a "textarea" field for entering lists of positions. All coordinates refer to the genome freeze you specify. Furthermore, you can specify whether your coordinates are "zero-based" or "one-based". In the "zero-based" system, the very first position in a chromosome has a coordinate of zero. The "one-based" coordinate is the one most commonly used.
Chromosomes can be equivalently specified as "chr1", "chrX", etc., or as "1", "X", etc.
Position coordinates can be specified as plain numbers (e.g. 42101) or adorned with commas (e.g. 42,101).
A range is specified as two position coordinates joined by a dash (e.g. 142101-142125). The second coordinate may not be less than the first.
A series of positions and/or ranges can be separated (delimited) by commas, semicolons, spaces and other whitespace.
Rules #2 and #4 don't really clash:
"142,101" is interpreted as a single number: 142101
"142, 101" is interpreted as two numbers: 101 and 142
"1142,101" and "101,1142" are interpreted as two numbers: 101 and 1142
To query a single position or range, you could enter its chromosome and coordinate(s) in their respective fields.
To query a few positions/ranges on one chromosome, you could enter the chromosome in the chromosome field, and the coordinates in the coordinates field - separating them with commas, spaces, etc.
coordinates: 42101,77119,555,911(note: those are three numbers!)
To query many position/ranges, on one or more chromosomes, leave the chromosome and coordinate fields blank, and use instead the "textarea" field. As you can see in the examples below, this field can accept quite a variety of formats...