![]() ![]() '=' (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. But validation is not working for entry of numeric value entry alone.Also I need to block a date before 1900. īut when you get a Date object from string, the result can be valid or not. How to validate date in dd/MM/yyyy format in javascript I am using the below regular expression. ![]() 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. Date validation in the dd/mm/yyyy format for years 1000 (i.e 999 or 0999 not matching) and taking february leap years into account. ^ means begin, \d means expect a digit within else if(isNaN( can do it with Regular Expressions, but it makes no practical sense. regular expression to match required date format In this first example, we’re giving an easy to understand dd/mm/yyyy date validation. ![]() The next step is validating the form’s only input, so that it matches that of a date. The HTML elements we’ll need from now on. ![]()
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