td colspan/rowspan Grid Coverage Validator
Checks explicit cell rectangles within one bounded table row group using zero-based starts and normalized colspan/rowspan. Rowspan 0 reaches the group end. At most 10,000 grid slots and 1000 cells are allowed; this does not derive cell positions from HTML.
Description
Table cells occupy rectangular grid slots.
Table cells occupy rectangular grid slots. Rowspan and colspan can leave gaps or cause overlapping coverage even when each individual span is positive.1
Checks explicit cell rectangles within one bounded table row group using zero-based starts and normalized colspan/rowspan. Rowspan 0 reaches the group end. At most 10,000 grid slots and 1000 cells are allowed; this does not derive cell positions from HTML.
When to use td colspan/rowspan Grid Coverage Validator
Use this for the following task: Checks explicit cell rectangles within one bounded table row group using zero-based starts and normalized colspan/rowspan. Rowspan 0 reaches the group end. At most 10,000 grid slots and 1000 cells are allowed; this does not derive cell positions from HTML.
Prepare the parsed attribute values, element states or ordered local lists requested below. Keep attribute presence separate from value.
How to use td colspan/rowspan Grid Coverage Validator and understand its results
- Prepare the parsed attribute values, element states or ordered local lists requested below. Keep attribute presence separate from value.
- Enter rows, columns, startRows, startColumns, rowspans, colspans using the field table, then run the tool.
- Read coveredSlots, uncoveredSlots, overlappingSlots, completeWithoutOverlap. Interpret flags, units, ordering and placeholder values using the rules below.
- Review any reported issue or failed check, correct the supplied values when appropriate, and verify the result in its intended context.
| Input field | Meaning | Value type and bounds | Requirement |
|---|---|---|---|
| rows | Rows | integer; minimum 1; maximum 100 | Required |
| columns | Columns | integer; minimum 1; maximum 100 | Required |
| startRows | Start Rows | list of integer; minimum entries 0; maximum entries 1000; each entry: integer; minimum 0 | Required |
| startColumns | Start Columns | list of integer; minimum entries 0; maximum entries 1000; each entry: integer; minimum 0 | Required |
| rowspans | Rowspans | list of integer; minimum entries 0; maximum entries 1000; each entry: integer; minimum 0; maximum 65534 | Required |
| colspans | Colspans | list of integer; minimum entries 0; maximum entries 1000; each entry: integer; minimum 1; maximum 1000 | Required |
Supply aligned zero-based cell starts and normalized spans for one row group. Rowspan 0 extends to that group’s end. Reject rectangles outside the grid, increment each covered slot, then count slots with zero, one or multiple occupants.2
completeWithoutOverlap = uncoveredSlots == 0 AND overlappingSlots == 0 This summarizes the declared operation. Units, indexing, inclusivity and exceptional cases are explained in the surrounding text.
| Output field | Meaning | Value type |
|---|---|---|
| coveredSlots | Covered Slots | integer |
| uncoveredSlots | Uncovered Slots | integer |
| overlappingSlots | Overlapping Slots | integer |
| completeWithoutOverlap | Complete Without Overlap | boolean |
{
"input": {
"rows": 2,
"columns": 2,
"startRows": [
0,
0
],
"startColumns": [
0,
1
],
"rowspans": [
0,
2
],
"colspans": [
1,
1
]
},
"output": {
"coveredSlots": 4,
"uncoveredSlots": 0,
"overlappingSlots": 0,
"completeWithoutOverlap": true
}
}Limitations and assumptions
The tool does not derive positions from HTML or resolve multiple row groups. It accepts at most 100 by 100 slots and 1000 cells.
This evaluates supplied local information; it does not fetch a page or run a browser. Malformed requests produce input errors. A successfully evaluated request can still contain false flags, empty result lists or a result outside the supplied threshold; those outcomes have the meanings stated above.
Alternative or Complementary methods
Choose colgroup span Count Calculator for this operation: Counts colgroup columns from normalized positive spans (at most 1000 each). When col children exist their spans determine the count and a group span attribute is nonconforming. For a complementary task, use caption vs summary Deprecated Lookup for this operation: Classifies a table caption element versus the obsolete summary attribute for current authoring conformance. This reports syntax status and caption semantics only.
Further background: HTML / accessibility reference: td colspan/rowspan Grid Coverage Validator.
References
Similar or alternative tools
- colgroup span Count Calculator
Counts colgroup columns from normalized positive spans (at most 1000 each). When col children exist their spans determine the count and a group span attribute is nonconforming.
- caption vs summary Deprecated Lookup
Classifies a table caption element versus the obsolete summary attribute for current authoring conformance. This reports syntax status and caption semantics only.