Make DataFrame.to_html output full content
- [ ] closes #17004
- [ ] tests added / passed
- [ ] passes `git diff upstream/master -u -- "*.py" | flake8 --diff`
- [ ] whatsnew entry

Hello @simonjayhawkins! Thanks for updating the PR.





Cheers ! There are no PEP8 issues in this Pull Request. :beers: 

##### Comment last updated on February 10, 2019 at 21:43 Hours UTC # [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/24841?src=pr&el=h1) Report
> Merging [#24841](https://codecov.io/gh/pandas-dev/pandas/pull/24841?src=pr&el=desc) into [master](https://codecov.io/gh/pandas-dev/pandas/commit/e984947ab42b2c95c5acbe37cf2e24786a51980d?src=pr&el=desc) will **increase** coverage by `<.01%`.
> The diff coverage is `100%`.

[![Impacted file tree graph](https://codecov.io/gh/pandas-dev/pandas/pull/24841/graphs/tree.svg?width=650&token=eZ4WkYLtcO&height=150&src=pr)](https://codecov.io/gh/pandas-dev/pandas/pull/24841?src=pr&el=tree)

```diff
@@            Coverage Diff             @@
##           master   #24841      +/-   ##
==========================================
+ Coverage   92.38%   92.39%   +<.01%     
==========================================
  Files         166      166              
  Lines       52390    52384       -6     
==========================================
- Hits        48402    48400       -2     
+ Misses       3988     3984       -4
```

| Flag | Coverage Δ | |
|---|---|---|
| #multiple | `90.81% <100%> (ø)` | :arrow_up: |
| #single | `42.89% <0%> (-0.03%)` | :arrow_down: |

| [Impacted Files](https://codecov.io/gh/pandas-dev/pandas/pull/24841?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [pandas/io/formats/html.py](https://codecov.io/gh/pandas-dev/pandas/pull/24841/diff?src=pr&el=tree#diff-cGFuZGFzL2lvL2Zvcm1hdHMvaHRtbC5weQ==) | `99.35% <100%> (+0.01%)` | :arrow_up: |
| [pandas/plotting/\_converter.py](https://codecov.io/gh/pandas-dev/pandas/pull/24841/diff?src=pr&el=tree#diff-cGFuZGFzL3Bsb3R0aW5nL19jb252ZXJ0ZXIucHk=) | `63.76% <0%> (-0.06%)` | :arrow_down: |
| [pandas/core/arrays/period.py](https://codecov.io/gh/pandas-dev/pandas/pull/24841/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvYXJyYXlzL3BlcmlvZC5weQ==) | `98.52% <0%> (ø)` | :arrow_up: |
| [pandas/core/indexes/period.py](https://codecov.io/gh/pandas-dev/pandas/pull/24841/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvaW5kZXhlcy9wZXJpb2QucHk=) | `92.06% <0%> (ø)` | :arrow_up: |
| [pandas/core/resample.py](https://codecov.io/gh/pandas-dev/pandas/pull/24841/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvcmVzYW1wbGUucHk=) | `97.23% <0%> (ø)` | :arrow_up: |
| [pandas/util/testing.py](https://codecov.io/gh/pandas-dev/pandas/pull/24841/diff?src=pr&el=tree#diff-cGFuZGFzL3V0aWwvdGVzdGluZy5weQ==) | `88.13% <0%> (+0.09%)` | :arrow_up: |
| [pandas/core/reshape/merge.py](https://codecov.io/gh/pandas-dev/pandas/pull/24841/diff?src=pr&el=tree#diff-cGFuZGFzL2NvcmUvcmVzaGFwZS9tZXJnZS5weQ==) | `94.4% <0%> (+0.13%)` | :arrow_up: |
| [pandas/plotting/\_timeseries.py](https://codecov.io/gh/pandas-dev/pandas/pull/24841/diff?src=pr&el=tree#diff-cGFuZGFzL3Bsb3R0aW5nL190aW1lc2VyaWVzLnB5) | `65.46% <0%> (+0.17%)` | :arrow_up: |
| [pandas/tseries/frequencies.py](https://codecov.io/gh/pandas-dev/pandas/pull/24841/diff?src=pr&el=tree#diff-cGFuZGFzL3RzZXJpZXMvZnJlcXVlbmNpZXMucHk=) | `97.7% <0%> (+0.62%)` | :arrow_up: |

------

[Continue to review full report at Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/24841?src=pr&el=continue).
> **Legend** - [Click here to learn more](https://docs.codecov.io/docs/codecov-delta)
> `Δ = absolute <relative> (impact)`, `ø = not affected`, `? = missing data`
> Powered by [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/24841?src=pr&el=footer). Last update [e984947...bfad29e](https://codecov.io/gh/pandas-dev/pandas/pull/24841?src=pr&el=lastupdated). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments).
 # [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/24841?src=pr&el=h1) Report
> Merging [#24841](https://codecov.io/gh/pandas-dev/pandas/pull/24841?src=pr&el=desc) into [master](https://codecov.io/gh/pandas-dev/pandas/commit/5f73594d49ea06ada4c6779006c00aaf41935595?src=pr&el=desc) will **increase** coverage by `<.01%`.
> The diff coverage is `100%`.

[![Impacted file tree graph](https://codecov.io/gh/pandas-dev/pandas/pull/24841/graphs/tree.svg?width=650&token=eZ4WkYLtcO&height=150&src=pr)](https://codecov.io/gh/pandas-dev/pandas/pull/24841?src=pr&el=tree)

```diff
@@            Coverage Diff             @@
##           master   #24841      +/-   ##
==========================================
+ Coverage   91.93%   91.93%   +<.01%     
==========================================
  Files         166      166              
  Lines       52187    52193       +6     
==========================================
+ Hits        47978    47984       +6     
  Misses       4209     4209
```

| Flag | Coverage Δ | |
|---|---|---|
| #multiple | `90.48% <100%> (ø)` | :arrow_up: |
| #single | `42.13% <0%> (-0.01%)` | :arrow_down: |

| [Impacted Files](https://codecov.io/gh/pandas-dev/pandas/pull/24841?src=pr&el=tree) | Coverage Δ | |
|---|---|---|
| [pandas/io/formats/html.py](https://codecov.io/gh/pandas-dev/pandas/pull/24841/diff?src=pr&el=tree#diff-cGFuZGFzL2lvL2Zvcm1hdHMvaHRtbC5weQ==) | `99.35% <100%> (+0.01%)` | :arrow_up: |

------

[Continue to review full report at Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/24841?src=pr&el=continue).
> **Legend** - [Click here to learn more](https://docs.codecov.io/docs/codecov-delta)
> `Δ = absolute <relative> (impact)`, `ø = not affected`, `? = missing data`
> Powered by [Codecov](https://codecov.io/gh/pandas-dev/pandas/pull/24841?src=pr&el=footer). Last update [5f73594...cd63aa5](https://codecov.io/gh/pandas-dev/pandas/pull/24841?src=pr&el=lastupdated). Read the [comment docs](https://docs.codecov.io/docs/pull-request-comments).
 OK. so considering that this bug has such a simple workaround that it is unlikely to be a real issue to most users then i think the best way forward here is to _also_ include an api change in _this_ PR and defer to 0.25.

if I add a `max_colwidth` parameter to `to_html` that just takes an non-negative int (to be consistent with the `max_cols` and `max_rows` parameters of `to_html`), users prefering the current (incorrect) behaviour could then just use `to_html(max_colwidth=pd.options.display.max_colwidth)`

i think issue #17004 could then be considered fully closed. thanks @simonjayhawkins 