To calculate the total of the values in an array, a loop is used with an accumulator variable. Show
Random numbers are useful in simulation programs where the computer must randomly decide how an object will behave Checking for reasonableness of data is programmatically impossible When a function finishes, it returns a value back to the part of the program that called it. Some programming languages provide this specialized loop that steps through an array, retrieving the value of each element Access the individual elements in an array by using their ________ Multiple-dimensional arrays can be used to model data that occurs in multiple sets. The toInteger function accepts a real number as its argument and preserves any fractional part in the returned number In the IPO chart, the ________ column describes the data that is passed to the function as arguments
_______ happens when an input operation attempts to read data, but there is no data to read Array bounds checking happens at runtime, which is while the program is running. Input validation is not needed if the program is well designed Which of the following errors occur when a real value is attempted to be assigned to an integer variable? Which is the simplest search technique to use to find an item in an array? The practice of anticipating errors that can happen while a program is running and designing the program to avoid those errors is called defensive programming The first step in calculating the average of the values in an array is to get the total of the values What is the term used for the number inside the bracket that specifies the number of values that an array can hold? The purpose of the ________ is to get the first input value for the validation of a loop Which of the following is not a check for data accuracy? Time measurements ZIP codes in correct format and valid Salary within the allowable range Processing a large number of items in a(n) ________ is usually easier than processing a large number of items stored in separate variables The function ________ specifies the return data type, name of the function, and the parameter variable(s). Unlike variables, arrays need to be initialized separately from the declaration. The term ________ is used to describe any mechanism that accepts input, performs some operation that cannot be seen on the input, and produces output The priming read is needed when a pretest loop is executed Library functions are built into the programming language, and can be called any time they are needed. The empty read is not an obvious input error and is a difficult one to handle. If, when asked for a date of birth, the user enters a future date, this error should be caught by a ________ check. Most programming languages let you assign an integer value to a real variable without causing an error What term is used in the ending terminal symbol of a function flowchart? What is the famous saying among computer programmers that refers to the fact that computers cannot tell the difference between good and bad data? The How an The available types are as follows: The This section provides a table listing all the attributes with a brief description. This table is followed by a list describing each attribute in greater detail, along with which input types they are associated with. Those that are common to most or all input types are defined in greater detail below. Attributes that are unique to particular input types—or attributes which are common to all input types but have special behaviors when used on a given input type—are instead documented
on those types' pages. Attributes for the A few additional non-standard attributes are listed following the descriptions of the standard attributes. Valid for the Valid for the (Not a Boolean attribute!) The The
See The
HTML autocomplete attribute for additional information, including information on password security and how A Boolean attribute which, if present, indicates that the input should automatically have focus when the page has finished loading (or when the Note: An element with the No more than one element in the document may have the The Warning: Automatically focusing a form control can confuse visually-impaired people using screen-reading technology and people with cognitive impairments. When Use careful consideration for accessibility when applying the Introduced in the HTML Media Capture specification and valid for the Valid for both Note:
Unlike other input controls, a checkboxes and radio buttons value are only included in the submitted data if they are currently For example, if a checkbox whose Valid for When the form above is submitted, the input cause both the disabled A Boolean attribute which, if present, indicates that the user should not be able to interact with the input. Disabled inputs are typically rendered with a dimmer color or using some other form of indication that the field is not available for use. Specifically, disabled inputs do not receive the Note: Although not required by
the specification, Firefox will by default persist the dynamic disabled state of an form A string specifying
the The Note: An input can only be associated with one form. formaction Valid for the formenctype
Valid for the formmethod Valid for the formnovalidate
Valid for the formtarget Valid for the height
Valid for the id Global attribute valid for all elements, including all the input types, it defines a unique identifier (ID) which must be unique in the whole document. Its purpose is to identify the
element when linking. The value is used as the value of the inputmode Global value valid for all elements, it provides a hint to browsers as to the type of virtual keyboard configuration to
use when editing this element or its contents. Values include list The value given to the It is valid on Per the specifications, the Depending on the browser, the user may see a custom color palette suggested, tic marks along a range, or even an input that opens like a
See the max
Valid for There is a special case: if the data type is periodic (such as for dates or times), the value of maxlength Valid for The input will fail constraint validation if the length of the text entered into the field is
greater than min Valid for This value must be less than or equal to the value of the There is a special case: if the data type is
periodic (such as for dates or times), the value of minlength Valid for The input will fail constraint validation if the length of the text entered into the field is fewer than multiple The Boolean name A string specifying a name for the input control. This name is submitted along with the control's value when the form data is submitted. Consider the There are two special cases:
The Only one radio button in a same-named group of radio buttons can be checked at a time. Selecting any radio button in that group automatically deselects any currently-selected radio button in the same group. The value of that one checked radio button is sent along with the name if the form is submitted, When tabbing into a series of same-named group of radio buttons, if one is checked, that one will receive focus. If they aren't grouped together in source order, if one of the group is checked, tabbing into the group starts when the first one in the group is encountered, skipping all those that aren't checked. In other words, if one is checked, tabbing skips the unchecked radio buttons in the group. If none are checked, the radio button group receives focus when the first button in the same name group is reached. Once one of the radio buttons in a group has focus, using the arrow keys will navigate through all the radio buttons of the same name, even if the radio buttons are not grouped together in the source order. When an input element is given a
When this code has run, Warning: Avoid giving form elements a pattern Valid for If the Note: If using the See Client-side validation for more information. placeholder Valid for Note: The readonly A Boolean attribute which, if present, indicates that the user should not be able to edit the value of the input. The See the HTML attribute: required
See Client-side validation and the HTML attribute: size Valid
for src Valid for the step Valid for If not explicitly included:
The value must be a positive number—integer or float—or the special value If For example, if you have Note: When the data entered by the user doesn't adhere to the stepping configuration, the value is considered invalid in constraint validation and will match the See Client-side validation for more information. tabindex Global attribute valid for all elements, including all the input types, an integer attribute indicating if the element can take input focus (is focusable), if it should participate to sequential keyboard navigation. As all input types except for input of type hidden are focusable, this attribute should not be used on form controls, because doing so would require the management of the focus order for all elements within the document with the risk of harming usability and accessibility if done incorrectly. title
Global attribute valid for all elements, including all input types, containing a text representing advisory information related to the element it belongs to. Such information can typically, but not necessarily, be presented to the user as a tooltip. The title should NOT be used as the primary explanation of the purpose of the form control. Instead, use the type A string specifying the type of control to render. For example, to create a checkbox, a value of Permitted values are listed in Input types above. value The input control's value. When specified in the HTML, this is the initial value, and from then on it can be altered or retrieved at any time using JavaScript to access the respective
width Valid for the Non-standard attributesThe following non-standard attributes are also available on some browsers. As a general rule, you should avoid using them unless it can't be helped. autocorrect Non-standard(Safari only). A string which indicates whether or not to activate automatic correction while the user is editing this field. Permitted values are: on Enable automatic correction of typos, as well as processing of text substitutions if any are configured. off Disable automatic correction and text substitutions. incremental Non-standardThe Boolean attribute If The orient Non-standardSimilar to the -moz-orient non-standard CSS property impacting the results Non-standardThe The value must be a non-negative decimal number. If not provided, or an invalid value is given, the browser's default maximum number of entries is used. webkitdirectory Non-standard
The Boolean Though originally implemented only for WebKit-based browsers, MethodsThe following methods are provided by the checkValidity() Returns reportValidity() Returns select() Selects the entire content of the setCustomValidity() Sets a custom message to display if the input element's value isn't valid. setRangeText() Sets the contents of the specified range of characters in the input element to a given string. A setSelectionRange() Selects the specified range of characters within a textual input element. Does nothing for inputs which aren't presented as text input fields. stepDown() Decrements the value of a numeric input by one, by default, or by the specified number of units. stepUp() Increments the value of a numeric input by one or by the specified number of units. CSSInputs, being replaced elements, have a few features not applicable to non form elements. There are CSS selectors that can specifically target form controls based on their UI features, also known as UI pseudo-classes. The input element can also be targeted by type with attribute selectors. There are some properties that are especially useful as well. UI pseudo-classesPseudo-classes exampleWe can style a checkbox label based on whether the checkbox is checked or not. In this example, we are styling the
Attribute selectorsIt is possible to target different types of form controls based on their
::placeholderBy default, the appearance of placeholder text is a translucent or light gray. The
Only the subset of CSS properties that apply to the appearanceThe You could make a Setting caret-colorA property specific to text entry-related elements is the CSS
HTML
CSS
Resultobject-position and object-fitIn certain cases (typically involving non-textual inputs and specialized interfaces), the StylingAdditional featuresLabelsLabels are needed to associate
assistive text with an Associated labelsThe semantic pairing of It does not suffice to have plain text adjacent to the
The first example is inaccessible: no relationship exists between the prompt and the In addition to an accessible name, the label provides a larger 'hit' area for mouse and touch screen users to click on or touch. By pairing a As web developers, it's important that we never assume that people will know all the things that we know. The diversity of people using the web—and by extension your website—practically guarantees that some of your site's visitors will have some variation in thought processes and/or circumstances that leads them to interpret your forms very differently from you without clear and properly-presented labels. Placeholders are not accessibleThe Not only is the placeholder not accessible to screen readers, but once the user enters any text into the form control, or if the form control already has a value, the placeholder disappears. Browsers with automatic page translation features may
skip over attributes when translating, meaning the Note: Don't use the Client-side validationWarning: Client-side validation is useful, but it does not guarantee that the server will receive valid data. If the data must be in a specific format, always verify it also on the server-side,
and return a In addition to using CSS to style inputs based on the Some input types and
other attributes place limits on what values are valid for a given input. For example, For the input types whose domain of possible values is
periodic (that is, at the highest possible value, the values wrap back around to the beginning rather than ending), it's possible for the values of the
Specific attributes and their values can lead to a specific error If a form control doesn't have the We can set limits on what values we accept, and supporting browsers will natively validate these form values and alert the user if there is a mistake when the form is submitted. In addition to the errors described in the table above, the
For each of these Boolean properties, a value of If there is an error, supporting browsers will both alert the user and prevent the form from being submitted. A word of caution: if a custom error is set to a truthy value (anything other than the empty string or
The last line, setting the custom validity message to the empty string is vital. If the user makes an error, and the validity is set, it will fail to submit, even if all of the values are valid, until the message is Custom validation error exampleIf you want to present a custom error message when a field fails to validate, you need to use the
Constraint validation features available on
The basic HTML form validation features will cause this to produce a default error message if you try to submit the form with either no valid filled in, or a value that does not match the If you wanted to instead display custom error messages, you could use JavaScript like the following:
The example renders like so: In brief:
Note: Always validate input constraints both client side and server side. Constraint validation doesn't remove the need for validation on the server side. Invalid values can still be sent by older browsers or by bad actors. Note: Firefox supported a proprietary error attribute — LocalizationThe allowed inputs for certain Firefox uses the following heuristics to determine the locale to validate the user's input (at least for
Technical summaryAccessibility concernsLabelsWhen including inputs, it is an accessibility requirement to add labels along side. This is needed so those who use assistive technologies can tell what the input is for. Also, clicking or touching a label gives focus to the label's associated form control. This improves the accessibility and usability for sighted users, increases the area a user can click or touch to activate the form control. This is especially useful (and even needed) for radio buttons and checkboxes, which are tiny. For more information about labels in general see Labels . The following is an example of how to associate the
SizeInteractive elements such as form input should provide an area large enough that it is easy to activate them. This helps a variety of people, including people with motor control issues and people using non-precise forms of input such as a stylus or fingers. A minimum interactive size of 44×44 CSS pixels is recommended.
Specifications
Browser compatibilityBCD tables only load in the browser See alsoWhat is another term for input validation?Input Validation, also known as data validation, is the testing of any input (or data) provided by a user or application against expected criteria.
Which of the following library functions could be used to determine the length of a string?You can get the length of a string using the strlen function. This function is declared in the header file string.
What is the first input value for the validation of a loop?The first input operation—just before the loop — is called a priming read, and its purpose is to get the first input value that will be tested by the validation loop.
What does the term garbage in garbage out mean quizlet?What does the phrase "garbage in, garbage out" mean? It means that if bad data (garbage) is provided as input to a program, the program will produce bad data (garbage) as output.
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