valid_elements

The valid_elements option defines which elements will remain in the edited text when the editor saves. You can use this to limit the returned HTML to a subset.

This option contains a comma separated list of element conversion chunks. Each chunk contains information about how one element and its attributes should be treated. The default rule set for this option is specified below.

Control characters:

NameSummary
@

Rules with this name will be applied to all elements defined after this rule. So @[attr1|attr2] will enable attr1 and attr2 for all elements, but element1,@[attr1|attr2],element2,element3 will enable attr1 and attr2 only for element2 and element3.

If applied in extended_valid_elements, it is only effective for the elements in the extended_valid_elements list.

, Separates element chunk definitions.
/ Separates element synonymous. The first element is the one that will be output.
| Separates attribute definitions.
[ Starts a new attribute list for an element definition.
] Ends an attribute list for an element definition.
! Makes attributes required. If none of the required attributes are set, the element will be removed. For example, "!href".
= Makes the attribute default to the specified value. For example, "target=_blank"
: Forces the attribute to the specified value. For example, "border:0"
< Verifies the value of an attribute (only the listed values are allowed). For example, "target<_blank?_self"
? Separates attribute verification values. See above.
+ Makes the element open if no child nodes exists. For example, "+a".
- Enables removal of empty elements such as <strong />. For example, "-strong".
# Enables padding of empty elements. This will pad with &nbsp; if they are empty. For example, "#p".

Wildcards such as *,+,? may be used in element or attribute name matching.

Special variables:

NameSummary
{$uid} Results in a unique ID. For example, "p[id:{$uid}]".

Use *[*] to include all elements and all attributes. This can be very useful when used with the invalid_elements option. Example of usage of the valid_elements option:

This example string tells TinyMCE to remove all elements that are not a "a, strong, div or br" element, convert "b" elements to "strong" elements, default "target" to "_blank" and keep the "href", "target" and "align" attributes of the elements.

tinyMCE.init({
...
valid_elements : "a[href|target=_blank],strong/b,div[align],br"
});

Duplicate Attribute Warning

Be careful not to duplicate attributes in the definitions as this may cause tinyMCE to render duplicate attributes in the output. For example, if you have

 ... //bad code: dir and style listed twice
"blockquote[dir|style|cite|class|dir<ltr?rtl|id|lang|onclick|ondblclick"
+"|onkeydown|onkeypress|onkeyup|onmousedown|onmousemove|onmouseout"
+"|onmouseover|onmouseup|style|title]"
...

then if you happen to have a <blockquote> element in your code with style= or dir= attributes, the editor will cause each of those attributes to be duplicated in the output, which will result in invalid XHTML. (This is related to bug 1824716 - Duplicate attributes caused by valid_elements on the SourceForge tracker.)

Default rule set:

This is the default string used by TinyMCE to clean up the HTML contents.

valid_elements : "@[id|class|style|title|dir<ltr?rtl|lang|xml::lang|onclick|ondblclick|"
+ "onmousedown|onmouseup|onmouseover|onmousemove|onmouseout|onkeypress|"
+ "onkeydown|onkeyup],a[rel|rev|charset|hreflang|tabindex|accesskey|type|"
+ "name|href|target|title|class|onfocus|onblur],strong/b,em/i,strike,u,"
+ "#p,-ol[type|compact],-ul[type|compact],-li,br,img[longdesc|usemap|"
+ "src|border|alt=|title|hspace|vspace|width|height|align],-sub,-sup,"
+ "-blockquote,-table[border=0|cellspacing|cellpadding|width|frame|rules|"
+ "height|align|summary|bgcolor|background|bordercolor],-tr[rowspan|width|"
+ "height|align|valign|bgcolor|background|bordercolor],tbody,thead,tfoot,"
+ "#td[colspan|rowspan|width|height|align|valign|bgcolor|background|bordercolor"
+ "|scope],#th[colspan|rowspan|width|height|align|valign|scope],caption,-div,"
+ "-span,-code,-pre,address,-h1,-h2,-h3,-h4,-h5,-h6,hr[size|noshade],-font[face"
+ "|size|color],dd,dl,dt,cite,abbr,acronym,del[datetime|cite],ins[datetime|cite],"
+ "object[classid|width|height|codebase|*],param[name|value|_value],embed[type|width"
+ "|height|src|*],script[src|type],map[name],area[shape|coords|href|alt|target],bdo,"
+ "button,col[align|char|charoff|span|valign|width],colgroup[align|char|charoff|span|"
+ "valign|width],dfn,fieldset,form[action|accept|accept-charset|enctype|method],"
+ "input[accept|alt|checked|disabled|maxlength|name|readonly|size|src|type|value],"
+ "kbd,label[for],legend,noscript,optgroup[label|disabled],option[disabled|label|selected|value],"
+ "q[cite],samp,select[disabled|multiple|name|size],small,"
+ "textarea[cols|rows|disabled|name|readonly],tt,var,big"

Full XHTML rule set:

The following will validate that the page complies fully with the XHTML specification.

Please note that using this may slow down performance when TinyMCE is cleaning up the document (on save etc). If you use very large bodies of text, it is recommended that you stick with the default rule set, because it should be sufficient for most people.

valid_elements : ""
+"a[accesskey|charset|class|coords|dir<ltr?rtl|href|hreflang|id|lang|name"
+"|onblur|onclick|ondblclick|onfocus|onkeydown|onkeypress|onkeyup"
+"|onmousedown|onmousemove|onmouseout|onmouseover|onmouseup|rel|rev"
+"|shape<circle?default?poly?rect|style|tabindex|title|target|type],"
+"abbr[class|dir<ltr?rtl|id|lang|onclick|ondblclick|onkeydown|onkeypress"
+"|onkeyup|onmousedown|onmousemove|onmouseout|onmouseover|onmouseup|style"
+"|title],"
+"acronym[class|dir<ltr?rtl|id|id|lang|onclick|ondblclick|onkeydown|onkeypress"
+"|onkeyup|onmousedown|onmousemove|onmouseout|onmouseover|onmouseup|style"
+"|title],"
+"address[class|align|dir<ltr?rtl|id|lang|onclick|ondblclick|onkeydown"
+"|onkeypress|onkeyup|onmousedown|onmousemove|onmouseout|onmouseover"
+"|onmouseup|style|title],"
+"applet[align<bottom?left?middle?right?top|alt|archive|class|code|codebase"
+"|height|hspace|id|name|object|style|title|vspace|width],"
+"area[accesskey|alt|class|coords|dir<ltr?rtl|href|id|lang|nohref<nohref"
+"|onblur|onclick|ondblclick|onfocus|onkeydown|onkeypress|onkeyup"
+"|onmousedown|onmousemove|onmouseout|onmouseover|onmouseup"
+"|shape<circle?default?poly?rect|style|tabindex|title|target],"
+"base[href|target],"
+"basefont[color|face|id|size],"
+"bdo[class|dir<ltr?rtl|id|lang|style|title],"
+"big[class|dir<ltr?rtl|id|lang|onclick|ondblclick|onkeydown|onkeypress"
+"|onkeyup|onmousedown|onmousemove|onmouseout|onmouseover|onmouseup|style"
+"|title],"
+"blockquote[cite|class|dir<ltr?rtl|id|lang|onclick|ondblclick"
+"|onkeydown|onkeypress|onkeyup|onmousedown|onmousemove|onmouseout"
+"|onmouseover|onmouseup|style|title],"
+"body[alink|background|bgcolor|class|dir<ltr?rtl|id|lang|link|onclick"
+"|ondblclick|onkeydown|onkeypress|onkeyup|onload|onmousedown|onmousemove"
+"|onmouseout|onmouseover|onmouseup|onunload|style|title|text|vlink],"
+"br[class|clear<all?left?none?right|id|style|title],"
+"button[accesskey|class|dir<ltr?rtl|disabled<disabled|id|lang|name|onblur"
+"|onclick|ondblclick|onfocus|onkeydown|onkeypress|onkeyup|onmousedown"
+"|onmousemove|onmouseout|onmouseover|onmouseup|style|tabindex|title|type"
+"|value],"
+"caption[align<bottom?left?right?top|class|dir<ltr?rtl|id|lang|onclick"
+"|ondblclick|onkeydown|onkeypress|onkeyup|onmousedown|onmousemove"
+"|onmouseout|onmouseover|onmouseup|style|title],"
+"center[class|dir<ltr?rtl|id|lang|onclick|ondblclick|onkeydown|onkeypress"
+"|onkeyup|onmousedown|onmousemove|onmouseout|onmouseover|onmouseup|style"
+"|title],"
+"cite[class|dir<ltr?rtl|id|lang|onclick|ondblclick|onkeydown|onkeypress"
+"|onkeyup|onmousedown|onmousemove|onmouseout|onmouseover|onmouseup|style"
+"|title],"
+"code[class|dir<ltr?rtl|id|lang|onclick|ondblclick|onkeydown|onkeypress"
+"|onkeyup|onmousedown|onmousemove|onmouseout|onmouseover|onmouseup|style"
+"|title],"
+"col[align<center?char?justify?left?right|char|charoff|class|dir<ltr?rtl|id"
+"|lang|onclick|ondblclick|onkeydown|onkeypress|onkeyup|onmousedown"
+"|onmousemove|onmouseout|onmouseover|onmouseup|span|style|title"
+"|valign<baseline?bottom?middle?top|width],"
+"colgroup[align<center?char?justify?left?right|char|charoff|class|dir<ltr?rtl"
+"|id|lang|onclick|ondblclick|onkeydown|onkeypress|onkeyup|onmousedown"
+"|onmousemove|onmouseout|onmouseover|onmouseup|span|style|title"
+"|valign<baseline?bottom?middle?top|width],"
+"dd[class|dir<ltr?rtl|id|lang|onclick|ondblclick|onkeydown|onkeypress|onkeyup"
+"|onmousedown|onmousemove|onmouseout|onmouseover|onmouseup|style|title],"
+"del[cite|class|datetime|dir<ltr?rtl|id|lang|onclick|ondblclick|onkeydown"
+"|onkeypress|onkeyup|onmousedown|onmousemove|onmouseout|onmouseover"
+"|onmouseup|style|title],"
+"dfn[class|dir<ltr?rtl|id|lang|onclick|ondblclick|onkeydown|onkeypress"
+"|onkeyup|onmousedown|onmousemove|onmouseout|onmouseover|onmouseup|style"
+"|title],"
+"dir[class|compact<compact|dir<ltr?rtl|id|lang|onclick|ondblclick|onkeydown"
+"|onkeypress|onkeyup|onmousedown|onmousemove|onmouseout|onmouseover"
+"|onmouseup|style|title],"
+"div[align<center?justify?left?right|class|dir<ltr?rtl|id|lang|onclick"
+"|ondblclick|onkeydown|onkeypress|onkeyup|onmousedown|onmousemove"
+"|onmouseout|onmouseover|onmouseup|style|title],"
+"dl[class|compact<compact|dir<ltr?rtl|id|lang|onclick|ondblclick|onkeydown"
+"|onkeypress|onkeyup|onmousedown|onmousemove|onmouseout|onmouseover"
+"|onmouseup|style|title],"
+"dt[class|dir<ltr?rtl|id|lang|onclick|ondblclick|onkeydown|onkeypress|onkeyup"
+"|onmousedown|onmousemove|onmouseout|onmouseover|onmouseup|style|title],"
+"em/i[class|dir<ltr?rtl|id|lang|onclick|ondblclick|onkeydown|onkeypress"
+"|onkeyup|onmousedown|onmousemove|onmouseout|onmouseover|onmouseup|style"
+"|title],"
+"fieldset[class|dir<ltr?rtl|id|lang|onclick|ondblclick|onkeydown|onkeypress"
+"|onkeyup|onmousedown|onmousemove|onmouseout|onmouseover|onmouseup|style"
+"|title],"
+"font[class|color|dir<ltr?rtl|face|id|lang|size|style|title],"
+"form[accept|accept-charset|action|class|dir<ltr?rtl|enctype|id|lang"
+"|method<get?post|name|onclick|ondblclick|onkeydown|onkeypress|onkeyup"
+"|onmousedown|onmousemove|onmouseout|onmouseover|onmouseup|onreset|onsubmit"
+"|style|title|target],"
+"frame[class|frameborder|id|longdesc|marginheight|marginwidth|name"
+"|noresize<noresize|scrolling<auto?no?yes|src|style|title],"
+"frameset[class|cols|id|onload|onunload|rows|style|title],"
+"h1[align<center?justify?left?right|class|dir<ltr?rtl|id|lang|onclick"
+"|ondblclick|onkeydown|onkeypress|onkeyup|onmousedown|onmousemove"
+"|onmouseout|onmouseover|onmouseup|style|title],"
+"h2[align<center?justify?left?right|class|dir<ltr?rtl|id|lang|onclick"
+"|ondblclick|onkeydown|onkeypress|onkeyup|onmousedown|onmousemove"
+"|onmouseout|onmouseover|onmouseup|style|title],"
+"h3[align<center?justify?left?right|class|dir<ltr?rtl|id|lang|onclick"
+"|ondblclick|onkeydown|onkeypress|onkeyup|onmousedown|onmousemove"
+"|onmouseout|onmouseover|onmouseup|style|title],"
+"h4[align<center?justify?left?right|class|dir<ltr?rtl|id|lang|onclick"
+"|ondblclick|onkeydown|onkeypress|onkeyup|onmousedown|onmousemove"
+"|onmouseout|onmouseover|onmouseup|style|title],"
+"h5[align<center?justify?left?right|class|dir<ltr?rtl|id|lang|onclick"
+"|ondblclick|onkeydown|onkeypress|onkeyup|onmousedown|onmousemove"
+"|onmouseout|onmouseover|onmouseup|style|title],"
+"h6[align<center?justify?left?right|class|dir<ltr?rtl|id|lang|onclick"
+"|ondblclick|onkeydown|onkeypress|onkeyup|onmousedown|onmousemove"
+"|onmouseout|onmouseover|onmouseup|style|title],"
+"head[dir<ltr?rtl|lang|profile],"
+"hr[align<center?left?right|class|dir<ltr?rtl|id|lang|noshade<noshade|onclick"
+"|ondblclick|onkeydown|onkeypress|onkeyup|onmousedown|onmousemove"
+"|onmouseout|onmouseover|onmouseup|size|style|title|width],"
+"html[dir<ltr?rtl|lang|version],"
+"iframe[align<bottom?left?middle?right?top|class|frameborder|height|id"
+"|longdesc|marginheight|marginwidth|name|scrolling<auto?no?yes|src|style"
+"|title|width],"
+"img[align<bottom?left?middle?right?top|alt|border|class|dir<ltr?rtl|height"
+"|hspace|id|ismap<ismap|lang|longdesc|name|onclick|ondblclick|onkeydown"
+"|onkeypress|onkeyup|onmousedown|onmousemove|onmouseout|onmouseover"
+"|onmouseup|src|style|title|usemap|vspace|width],"
+"input[accept|accesskey|align<bottom?left?middle?right?top|alt"
+"|checked<checked|class|dir<ltr?rtl|disabled<disabled|id|ismap<ismap|lang"
+"|maxlength|name|onblur|onclick|ondblclick|onfocus|onkeydown|onkeypress"
+"|onkeyup|onmousedown|onmousemove|onmouseout|onmouseover|onmouseup|onselect"
+"|readonly<readonly|size|src|style|tabindex|title"
+"|type<button?checkbox?file?hidden?image?password?radio?reset?submit?text"
+"|usemap|value],"
+"ins[cite|class|datetime|dir<ltr?rtl|id|lang|onclick|ondblclick|onkeydown"
+"|onkeypress|onkeyup|onmousedown|onmousemove|onmouseout|onmouseover"
+"|onmouseup|style|title],"
+"isindex[class|dir<ltr?rtl|id|lang|prompt|style|title],"
+"kbd[class|dir<ltr?rtl|id|lang|onclick|ondblclick|onkeydown|onkeypress"
+"|onkeyup|onmousedown|onmousemove|onmouseout|onmouseover|onmouseup|style"
+"|title],"
+"label[accesskey|class|dir<ltr?rtl|for|id|lang|onblur|onclick|ondblclick"
+"|onfocus|onkeydown|onkeypress|onkeyup|onmousedown|onmousemove|onmouseout"
+"|onmouseover|onmouseup|style|title],"
+"legend[align<bottom?left?right?top|accesskey|class|dir<ltr?rtl|id|lang"
+"|onclick|ondblclick|onkeydown|onkeypress|onkeyup|onmousedown|onmousemove"
+"|onmouseout|onmouseover|onmouseup|style|title],"
+"li[class|dir<ltr?rtl|id|lang|onclick|ondblclick|onkeydown|onkeypress|onkeyup"
+"|onmousedown|onmousemove|onmouseout|onmouseover|onmouseup|style|title|type"
+"|value],"
+"link[charset|class|dir<ltr?rtl|href|hreflang|id|lang|media|onclick"
+"|ondblclick|onkeydown|onkeypress|onkeyup|onmousedown|onmousemove"
+"|onmouseout|onmouseover|onmouseup|rel|rev|style|title|target|type],"
+"map[class|dir<ltr?rtl|id|lang|name|onclick|ondblclick|onkeydown|onkeypress"
+"|onkeyup|onmousedown|onmousemove|onmouseout|onmouseover|onmouseup|style"
+"|title],"
+"menu[class|compact<compact|dir<ltr?rtl|id|lang|onclick|ondblclick|onkeydown"
+"|onkeypress|onkeyup|onmousedown|onmousemove|onmouseout|onmouseover"
+"|onmouseup|style|title],"
+"meta[content|dir<ltr?rtl|http-equiv|lang|name|scheme],"
+"noframes[class|dir<ltr?rtl|id|lang|onclick|ondblclick|onkeydown|onkeypress"
+"|onkeyup|onmousedown|onmousemove|onmouseout|onmouseover|onmouseup|style"
+"|title],"
+"noscript[class|dir<ltr?rtl|id|lang|style|title],"
+"object[align<bottom?left?middle?right?top|archive|border|class|classid"
+"|codebase|codetype|data|declare|dir<ltr?rtl|height|hspace|id|lang|name"
+"|onclick|ondblclick|onkeydown|onkeypress|onkeyup|onmousedown|onmousemove"
+"|onmouseout|onmouseover|onmouseup|standby|style|tabindex|title|type|usemap"
+"|vspace|width],"
+"ol[class|compact<compact|dir<ltr?rtl|id|lang|onclick|ondblclick|onkeydown"
+"|onkeypress|onkeyup|onmousedown|onmousemove|onmouseout|onmouseover"
+"|onmouseup|start|style|title|type],"
+"optgroup[class|dir<ltr?rtl|disabled<disabled|id|label|lang|onclick"
+"|ondblclick|onkeydown|onkeypress|onkeyup|onmousedown|onmousemove"
+"|onmouseout|onmouseover|onmouseup|style|title],"
+"option[class|dir<ltr?rtl|disabled<disabled|id|label|lang|onclick|ondblclick"
+"|onkeydown|onkeypress|onkeyup|onmousedown|onmousemove|onmouseout"
+"|onmouseover|onmouseup|selected<selected|style|title|value],"
+"p[align<center?justify?left?right|class|dir<ltr?rtl|id|lang|onclick"
+"|ondblclick|onkeydown|onkeypress|onkeyup|onmousedown|onmousemove"
+"|onmouseout|onmouseover|onmouseup|style|title],"
+"param[id|name|type|value|valuetype<DATA?OBJECT?REF],"
+"pre/listing/plaintext/xmp[align|class|dir<ltr?rtl|id|lang|onclick|ondblclick"
+"|onkeydown|onkeypress|onkeyup|onmousedown|onmousemove|onmouseout"
+"|onmouseover|onmouseup|style|title|width],"
+"q[cite|class|dir<ltr?rtl|id|lang|onclick|ondblclick|onkeydown|onkeypress"
+"|onkeyup|onmousedown|onmousemove|onmouseout|onmouseover|onmouseup|style"
+"|title],"
+"s[class|dir<ltr?rtl|id|lang|onclick|ondblclick|onkeydown|onkeypress|onkeyup"
+"|onmousedown|onmousemove|onmouseout|onmouseover|onmouseup|style|title],"
+"samp[class|dir<ltr?rtl|id|lang|onclick|ondblclick|onkeydown|onkeypress"
+"|onkeyup|onmousedown|onmousemove|onmouseout|onmouseover|onmouseup|style"
+"|title],"
+"script[charset|defer|language|src|type],"
+"select[class|dir<ltr?rtl|disabled<disabled|id|lang|multiple<multiple|name"
+"|onblur|onchange|onclick|ondblclick|onfocus|onkeydown|onkeypress|onkeyup"
+"|onmousedown|onmousemove|onmouseout|onmouseover|onmouseup|size|style"
+"|tabindex|title],"
+"small[class|dir<ltr?rtl|id|lang|onclick|ondblclick|onkeydown|onkeypress"
+"|onkeyup|onmousedown|onmousemove|onmouseout|onmouseover|onmouseup|style"
+"|title],"
+"span[align<center?justify?left?right|class|dir<ltr?rtl|id|lang|onclick|ondblclick|onkeydown"
+"|onkeypress|onkeyup|onmousedown|onmousemove|onmouseout|onmouseover"
+"|onmouseup|style|title],"
+"strike[class|class|dir<ltr?rtl|id|lang|onclick|ondblclick|onkeydown"
+"|onkeypress|onkeyup|onmousedown|onmousemove|onmouseout|onmouseover"
+"|onmouseup|style|title],"
+"strong/b[class|dir<ltr?rtl|id|lang|onclick|ondblclick|onkeydown|onkeypress"
+"|onkeyup|onmousedown|onmousemove|onmouseout|onmouseover|onmouseup|style"
+"|title],"
+"style[dir<ltr?rtl|lang|media|title|type],"
+"sub[class|dir<ltr?rtl|id|lang|onclick|ondblclick|onkeydown|onkeypress"
+"|onkeyup|onmousedown|onmousemove|onmouseout|onmouseover|onmouseup|style"
+"|title],"
+"sup[class|dir<ltr?rtl|id|lang|onclick|ondblclick|onkeydown|onkeypress"
+"|onkeyup|onmousedown|onmousemove|onmouseout|onmouseover|onmouseup|style"
+"|title],"
+"table[align<center?left?right|bgcolor|border|cellpadding|cellspacing|class"
+"|dir<ltr?rtl|frame|height|id|lang|onclick|ondblclick|onkeydown|onkeypress"
+"|onkeyup|onmousedown|onmousemove|onmouseout|onmouseover|onmouseup|rules"
+"|style|summary|title|width],"
+"tbody[align<center?char?justify?left?right|char|class|charoff|dir<ltr?rtl|id"
+"|lang|onclick|ondblclick|onkeydown|onkeypress|onkeyup|onmousedown"
+"|onmousemove|onmouseout|onmouseover|onmouseup|style|title"
+"|valign<baseline?bottom?middle?top],"
+"td[abbr|align<center?char?justify?left?right|axis|bgcolor|char|charoff|class"
+"|colspan|dir<ltr?rtl|headers|height|id|lang|nowrap<nowrap|onclick"
+"|ondblclick|onkeydown|onkeypress|onkeyup|onmousedown|onmousemove"
+"|onmouseout|onmouseover|onmouseup|rowspan|scope<col?colgroup?row?rowgroup"
+"|style|title|valign<baseline?bottom?middle?top|width],"
+"textarea[accesskey|class|cols|dir<ltr?rtl|disabled<disabled|id|lang|name"
+"|onblur|onclick|ondblclick|onfocus|onkeydown|onkeypress|onkeyup"
+"|onmousedown|onmousemove|onmouseout|onmouseover|onmouseup|onselect"
+"|readonly<readonly|rows|style|tabindex|title],"
+"tfoot[align<center?char?justify?left?right|char|charoff|class|dir<ltr?rtl|id"
+"|lang|onclick|ondblclick|onkeydown|onkeypress|onkeyup|onmousedown"
+"|onmousemove|onmouseout|onmouseover|onmouseup|style|title"
+"|valign<baseline?bottom?middle?top],"
+"th[abbr|align<center?char?justify?left?right|axis|bgcolor|char|charoff|class"
+"|colspan|dir<ltr?rtl|headers|height|id|lang|nowrap<nowrap|onclick"
+"|ondblclick|onkeydown|onkeypress|onkeyup|onmousedown|onmousemove"
+"|onmouseout|onmouseover|onmouseup|rowspan|scope<col?colgroup?row?rowgroup"
+"|style|title|valign<baseline?bottom?middle?top|width],"
+"thead[align<center?char?justify?left?right|char|charoff|class|dir<ltr?rtl|id"
+"|lang|onclick|ondblclick|onkeydown|onkeypress|onkeyup|onmousedown"
+"|onmousemove|onmouseout|onmouseover|onmouseup|style|title"
+"|valign<baseline?bottom?middle?top],"
+"title[dir<ltr?rtl|lang],"
+"tr[abbr|align<center?char?justify?left?right|bgcolor|char|charoff|class"
+"|rowspan|dir<ltr?rtl|id|lang|onclick|ondblclick|onkeydown|onkeypress"
+"|onkeyup|onmousedown|onmousemove|onmouseout|onmouseover|onmouseup|style"
+"|title|valign<baseline?bottom?middle?top],"
+"tt[class|dir<ltr?rtl|id|lang|onclick|ondblclick|onkeydown|onkeypress|onkeyup"
+"|onmousedown|onmousemove|onmouseout|onmouseover|onmouseup|style|title],"
+"u[class|dir<ltr?rtl|id|lang|onclick|ondblclick|onkeydown|onkeypress|onkeyup"
+"|onmousedown|onmousemove|onmouseout|onmouseover|onmouseup|style|title],"
+"ul[class|compact<compact|dir<ltr?rtl|id|lang|onclick|ondblclick|onkeydown"
+"|onkeypress|onkeyup|onmousedown|onmousemove|onmouseout|onmouseover"
+"|onmouseup|style|title|type],"
+"var[class|dir<ltr?rtl|id|lang|onclick|ondblclick|onkeydown|onkeypress"
+"|onkeyup|onmousedown|onmousemove|onmouseout|onmouseover|onmouseup|style"
+"|title]"

Full FlashMX 2004 rule set:

The following will validate that the page complies fully with the flashMX 2004 specification.

valid_elements : ""
+"a[href|target],"
+"b,"
+"br,"
+"font[color|face|size],"
+"img[src|id|width|height|align|hspace|vspace],"
+"i,"
+"li,"
+"p[align|class],"
+"h1,"
+"h2,"
+"h3,"
+"h4,"
+"h5,"
+"h6,"
+"span[class],"
+"textformat[blockindent|indent|leading|leftmargin|rightmargin|tabstops],"
+"u"

Reference: http://livedocs.adobe.com/flash/mx2004/main_7_2/wwhelp/wwhimpl/common/html/wwhelp.htm?context=Flash_MX_2004&file=00001040.html

Also see extended_valid_elements and invalid_elements for more configuration options.