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Display alert dialog box



uialert(fig,message,title) displays a modal dialog box in front of the specified figure window. The figure must be created with the uifigure function. The dialog box displays the specified message and has a title bar with the specified title. By default, the dialog box also contains an error icon and an OK button.


uialert(___,Name,Value) displays a dialog box with properties specified by one or more Name,Value arguments.


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Create a modal alert dialog box. The figure behind it is inaccessible until you close the dialog box.

fig = uifigure;
uialert(fig,'File not found','Invalid File');

Alert dialog box. The icon is a red octagon with an exclamation point. The title of the dialog box is "Invalid File" and the text is "File not found". The box has an OK button in the bottom right.

fig = uifigure;
message = {'Fire hazard!','Consider reducing temperature.'};

Warning dialog box. The text spans two lines. The first line says "Fire hazard!" and the second line says "Consider reducing temperature".

Create a figure and two matrices of different sizes.

fig = uifigure; 
A = rand(3);
B = ones(5);

Attempt to vertically concatenate the matrices. Handle any errors that occur by getting the error text and creating an alert dialog box in the figure, and then specify the error text as the dialog message. MATLAB® error text often includes HTML formatting, so specify the dialog interpreter as 'html'. The error is displayed with a link to the documentation for the vertcat function.

    C = vertcat(A,B);
catch ME 
    report = getReport(ME);
    uialert(fig,report,'Error Message','Interpreter','html');

Alert dialog box. The message says: "Error using vertcat. Dimensions of arrays being concatenated are not consistent". The word "vertcat" is a blue hyperlink.

Input Arguments

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Target figure, specified as a Figure object. The figure must be created with the uifigure function.

Message, specified as a character vector, cell array of character vectors, or string array. The message can be any length.

To display multiple lines of text, use a cell array of character vectors or a string array, where each element in the array is a different line of text.

Example: 'Invalid value'

Title, specified as a character vector or string scalar. Long titles truncate and are followed by ellipses. The exact length at which a title is truncated depends on your system setup.

Spaces replace format characters, such as the newline (\n) character.

Name-Value Arguments

Specify optional pairs of arguments as Name1=Value1,...,NameN=ValueN, where Name is the argument name and Value is the corresponding value. Name-value arguments must appear after other arguments, but the order of the pairs does not matter.

Before R2021a, use commas to separate each name and value, and enclose Name in quotes.

Example: 'Icon','warning'

The alert dialog box close request callback function, specified as one of these values:

  • Function handle.

  • Cell array in which the first element is a function handle. Subsequent elements in the cell array are the arguments to pass to the callback function.

  • Character vector that is a valid MATLAB expression. MATLAB evaluates this expression in the base workspace.

The CloseFcn callback executes when the app user dismisses the alert dialog box by clicking the close button in the title bar or clicking the OK button. The CloseFcn function also executes when the app user closes the figure window for which the alert dialog box displays from the MATLAB command line. You can close a figure window from the command line using the close function.

Icon, specified as a predefined icon or a custom icon.

Predefined Icon

This table lists the values for the predefined icons. For example, to show the check mark icon, specify the name-value pair 'Icon','success'.

'error' (default)

Red octagon with an exclamation point symbol.


Yellow triangle with an exclamation point symbol.


Blue square with the letter "i".


Blue circular icon with a question mark


Green circle with a check mark symbol.


No icon displays.

Custom Icon

Specify a custom icon as one of these values:

  • A character vector that specifies the file name of an SVG, JPEG, GIF, or PNG image that is on the MATLAB path. Alternatively, you can specify a full path to the image file.

  • A truecolor image array. See Image Types for more information.

Modal, specified as true or false.

A modal dialog box is one that makes the figure inaccessible until the dialog box is closed. However, it does not prevent additional dialog boxes from appearing.

Dialog text interpreter, specified as:

  • 'none' — Display literal characters.

  • 'tex'— Interpret text using a subset of TeX markup.

  • 'latex'— Interpret text using a subset of LaTeX markup.

  • 'html'— Interpret text using a subset of HTML markup.

TeX Markup

Use TeX markup to add superscripts and subscripts and to include special characters in the text.

Modifiers remain in effect until the end of the text. Superscripts and subscripts are an exception because they modify only the next character or the characters within the curly braces. When you set the interpreter to 'tex', the supported modifiers are as follows.

^{ }Superscript'text^{superscript}'
_{ }Subscript'text_{subscript}'
\bfBold font'\bf text'
\itItalic font'\it text'
\slOblique font (usually the same as italic font)'\sl text'
\rmNormal font'\rm text'
\fontname{specifier}Font name — Replace specifier with the name of a font family. You can use this in combination with other modifiers.'\fontname{Courier} text'
\fontsize{specifier}Font size —Replace specifier with a numeric scalar value in point units.'\fontsize{15} text'
\color{specifier}Font color — Replace specifier with one of these colors: red, green, yellow, magenta, blue, black, white, gray, darkGreen, orange, or lightBlue.'\color{magenta} text'
\color[rgb]{specifier}Custom font color — Replace specifier with a three-element RGB triplet.'\color[rgb]{0,0.5,0.5} text'

This table lists the supported special characters for the 'tex' interpreter.

Character SequenceSymbolCharacter SequenceSymbolCharacter SequenceSymbol

























































































































































LaTeX Markup

Use LaTeX markup to format and display mathematical expressions, equations, and special characters. Use dollar symbols around the marked up text. For example, use '$\int_1^{20} x^2 dx$' for inline mode or '$$\int_1^{20} x^2 dx$$' for display mode.

The displayed text uses the default LaTeX font style. You can use LaTeX markup to change the font style.

MATLAB supports most standard LaTeX math mode commands. For more information, see Supported LaTeX Commands.

HTML Markup

Use HTML markup to display links and customize font styles.

The interpreter supports a subset of HTML markup. As a general guideline, the interpreter supports text-related tags and styles. Unsupported tags and styles are ignored.

This table lists the supported elements and element attributes.

HTML ElementAttributesDescription
astyle, target, href, titleHyperlink
abbrstyle, titleAbbreviation or acronym
addressstyleContact information
articlestyleSelf-contained, independent content
asidestyleContent indirectly related to the main content
bstyleBold text
bdistyle, dirContent formatted in a different direction from surrounding text
bdostyle, dirContent formatted in a different direction from surrounding text
bigstyleText one font size level larger than surrounding text (obsolete in HTML5)
blockquotestyle, citeExtended quotation
brn/aLine break
captionstyleCaption or title of a table
centerstyleContent centered horizontally
citestyleTitle of a creative work
codestyleFragment of code
colstyle, align, valign, span, widthColumn within a table
colgroupstyle, align, valign, span, widthGroup of columns within a table
ddstyleTerm or value in a description list
delstyle, datetimeText that was deleted from a document
detailsstyle, openInteractive widget with text visible only when toggled to 'open' state
dlstyleDescription list
dtstyleTerm or value in a description list
emstyleEmphasized text (typically displayed in italic)
fontstyle, color, size, faceText with specified font properties (obsolete in HTML5)
h1. h2, h3, h4, h5, h6styleSection heading — <h1> is the highest level of heading and <h6> is the lowest
headerstyleIntroductory content
hrstyleThematic break
istyleText offset from the surrounding content — by default rendered as italic
insstyle, datetimeText inserted into a document
listyleItem in a list
markstyleMarked or highlighted text
olstyleOrdered list
prestylePreformatted text
sstyleText with a strikethrough
strikestyleText with a strikethrough (obsolete in HTML5)
sectionstyleStandalone section
smallstyleText one font size level smaller than surrounding text (obsolete in HTML5)
strongstyleText with strong importance
tablestyle, width, border, align, valignTable
tbodystyle, align, valignTable body
tdstyle, width, rowspan, colspan, align, valignTable data cell
tfootstyle, align, valignSet of table rows that summarize the table columns
thstyle, width, rowspan, colspan, align, valignTable data cell specified as a header of a group of cells
theadstyle, align, valignSet of table rows that specify the column heads
trstyle, rowspan, align, valignRow of table cells
ttstyleMonospace text (obsolete in HTML5)
ustyleText with an unarticulated annotation — by default rendered as an underline
ulstyleUnordered list

For more information about these elements, see

You can use HTML style attributes to format HTML content. A style attribute is a string of CSS attributes and their values.

These CSS attributes are supported:

  • background-color

  • border-bottom

  • border-bottom-color

  • border-bottom-left-radius

  • border-bottom-right-radius

  • border-bottom-style

  • border-bottom-width

  • border-left

  • border-left-color

  • border-left-style

  • border-left-width

  • border-radius

  • border-right

  • border-right-color

  • border-right-style

  • border-right-width

  • border-spacing

  • border-style

  • border-top

  • border-top-color

  • border-top-left-radius

  • border-top-right-radius

  • border-top-style

  • border-top-width

  • border-width

  • color

  • direction

  • font-family

  • font-size

  • font-style

  • font-weight

  • height

  • hidden

  • line-height

  • margin

  • margin-bottom

  • margin-left

  • margin-right

  • margin-top

  • max-height

  • max-width

  • min-height

  • min-width

  • overflow

  • overflow-wrap

  • overflow-x

  • overflow-y

  • padding

  • padding-bottom

  • padding-left

  • padding-right

  • padding-top

  • text-align

  • text-anchor

  • text-decoration

  • text-indent

  • text-overflow

  • text-shadow

  • text-transform

  • title

  • translate

  • white-space

  • width

For more information about these attributes, see

Version History

Introduced in R2016a

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