HTML5 defines a range of built-in functionality to validate common types of input, such as email addresses and dates.
In some situations, such as validating custom controls or supporting legacy browsers, additional scripting may be necessary to validate user input.
Forms frequently include required input that needs to be clearly identified using labels.
Also, the attribute can be added to form controls, to programmatically indicate that they are required.
Validation is the checking of data to see if it is sensible in the context being used.
Several different types of validation may be applied to the same data item.
Although information typed at a computer might be the most familiar, networks and external devices can also send data to a program.
Generally, this data will be of a specific type: for example, a user interface that requests a person’s name might be written to expect a series of alphabetic characters.
In addition to providing instructions, validate user input to help users avoid mistakes.If video does not work, try refreshing the page: Any data that can enter your program from an external source can be a potential source of problems.If external data is not checked to verify that it has the right type of information, the right amount of information, and the right structure of information, it can cause problems.I need to check based on which column it got invalid." id="ctl00_m_m_i_ctl00_gr_ctl01_bestanswerbody" class="textarea-bestanswerhidden" name="bestanswerbody" answerbody Id="4418109" / Valid table: Column A(Number) Column B(Date) Column C(Varchar2(10) Invalid table Column A(Number) Column B(Date) Column C(Varchar2(10) Column D(rejected all column i.e Column A, B, C) Note: In invalid table column D rejected column.I need to check based on which column it got invalid.