I’ve researched this but none of the code I use seems to work. South African ID numbers contain date of birth and gender. All I want is it to pull in that information and verify it when their ID number is entered into an input field, preferably in jQuery or javascript Any help is appreciated, Dawid Answ…
Tag: validation
Javascript Validation for a phone number (Numbers, spaces, dots, hyphens)
So I have this validation for alphanumeric’s (/^[A-Za-z0-9,+-]+$/) however I want a validation for a phone number which only allows Numbers, Spaces, Dots and Hyphens. What code would I use to check for those. Thanks Ben Answer According to my specifications its just Numbers, Spaces, Dots and Hyphens onl…
How to show setCustomValidity message/tooltip without submit event
I’m using forms basic validation to check if email is correct format, then the data is sent by Ajax where it checks if email address is already in use and did the user select country/state or left default values in select boxes. But for HTML5 form validation to be done submit event is needed, upon click…
How to programmatically calculate the contrast ratio between two colors?
Pretty straight-forward, take yellow and white: What law of physics on God’s Earth of universal constants, makes the fact that yellow text can’t be read on white backgrounds but blue text can? For the sake of my customizable widget I tried all possible color models that I found conversions functio…
Max characters in textarea with jquery
I have the following code, and I’m kind of stuck on what to do next. The idea is when you enter text into a text area a counter tells you how many characters you have left. Once you get to the max characters I want to stop allowing characters to be entered, or delete all the characters that were entered
Validation of file extension before uploading file
I am uploading images to a servlet. The validation whether the uploaded file is an image is done in server side only, by checking the magic numbers in the file header. Is there any way to validate the extensions in client side before submitting the form to servlet? As soon as I hit enter it starts uploading. …
JavaScript file upload size validation
Is there any way to check file size before uploading it using JavaScript? Answer Yes, you can use the File API for this. Here’s a complete example (see comments): Slightly off-topic, but: Note that client-side validation is no substitute for server-side validation. Client-side validation is purely to ma…
How can I check if a string is a valid number?
I’m hoping there’s something in the same conceptual space as the old VB6 IsNumeric() function? Answer 2nd October 2020: note that many bare-bones approaches are fraught with subtle bugs (eg. whitespace, implicit partial parsing, radix, coercion of arrays etc.) that many of the answers here fail to…