- Javascript date validation dd mm yyyy regular expression how to#
- Javascript date validation dd mm yyyy regular expression code#
The validity of the date in the Date object can be checked with the !isNan () function. A true value means that it does match the object specified. This property can be checked for the Date object by comparing it with the string ' '. For start, use this:This property is assigned internally during the creation of any object. You can also use regular expression to validate. The forward slashes / / mark the beginning and end of the regex.Wondering if Google is broken/blocked at your place.It is filled with tons and tons of examples. The regex variable stores a regular expression. The function takes a string in the form of YYYY-MM-DD as a parameter. AmitDiwan,We created a reusable function that checks if a string is a valid date, formatted as YYYY-MM-DD. The snapshot is as follows −, Above, the console displays TRUE i.e.
Output, This will produce the following output −, Now, I am picking a date.
Javascript date validation dd mm yyyy regular expression code#
Select the option "Open with Live Server" in VS Code editor. To run the above program, save the file name "anyName.html (index.html)" and right click on the file. I already saw that there is a JS Library. Now I want to check if the date is valid (so that the user isn't able to enter a date like ). I get the birthdate as a string in the following format: " yyyy-mm-dd ". I have a form with a do enter the birthdate of a person.
Javascript date validation dd mm yyyy regular expression how to#
How to check if a date is valid using Javascript.For invalid dates, the date object re-jigs the values turning them into a valid date. For valid dates, reading back the component parts of the date would reveal the same values you had initially set. It works by creating a new date object, and setting it to the date you want to check.
'=' (not '=') is important: it compares with 0 of numeric type, not mixing it, with, say, "0". Zero is a special case: it would be converted to False, but is certainly valid. '!!' converts result to Boolean, which will be true in all cases when the time is valid. Even if I assume that different browsers can do something else, they still should return a number for a valid Date object. In case of invalid date, the browsers I tried return NaN, but I did not check it up with the standard. In case of the valid time value, the function () returns an integer value, the number of milliseconds, which is the time span from the certain point of time in 1970: usage example var a = new Date( " 11:20:13") What would be the validation method? I would suggest this one: So, you simply need to obtain Date object and validate it, not string.
It's very typical for JavaScript technology. The specific feature of JavaScript Date constructors is: they don't throw exception, don't return "error code", nothing. Why doing two separate steps if you can do validation and construction in one step? This "validation through construction" is not error-prone, in contrast to your Regular Expression attempts, because the constructor "knows better" what is valid and what not. īut when you get a Date object from string, the result can be valid or not. So, you don't need validation per se, you only need to know if the string is "good enough" to be uses for creation of the Date object. Let me explain you a very general idea related to validation, which is applicable to many platforms, technologies and languages.įirst of all, think why would you need validation? You only need to validate your string if you plan to get a Date value from that string. You can do it with Regular Expressions, but it makes no practical sense.
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