CODEWITHSUNDEEP
javascriptjqueryhtmlregex
Leopold Joy
Leopold Joy

Reputation: 4660

Only allow characters that follow exact regex pattern

I am new to regex and have a question. I am validating a date/time text input and only want to allow characters that fit an exact pattern. This is the format:

Mar 19, 2014 at 2:00am

Obviously the date (in this case "19") and the hour (in this case "2") could be one or two characters long. On Javascript keyup, I need a regex expression that removes all characters that do not exactly fit this pattern. How can I do this with regex? This is the exact pattern:

I do not care that it is a valid date. I simply need the entered text to fit this format.

Thank you for your help!

Upvotes: 0

Views: 1525

Answers (1)

aelor
aelor

Reputation: 11116

[A-Za-z]{3}\s\d{1,2},\s\d{4}\sat\s\d{1,2}:\d{2}(am|pm)

will match your requirement exactly

demo here : http://regex101.com/r/rU8xT0\

using with js

var str = "Mar 1, 2014 at 2:00pm";
if( /[A-Za-z]{3}\s\d{1,2},\s\d{4}\sat\s\d{1,2}:\d{2}(am|pm)/.test(str)){
  console.log("pass");
}
else{
  console.log("fail");
}

and this is exactly what you want, this will check for values which are not correct and highlight accordingly, I am using jquery to add and remove the class

$("#text").keyup(function () {
    if (/[A-Za-z]{3}\s\d{1,2},\s\d{4}\sat\s\d{1,2}:\d{2}(am|pm)/.test($(this).val())) {
        $(this).removeClass('error');
        $(this).addClass('good');
    } else {
        $(this).removeClass('good');
        $(this).addClass('error');

    }
})

for OPs special requirement in js

var str = "Mar 1, 2014 at 2:00pmaur bahut sara kachra";
var res = str.replace(/([A-Za-z]{3}\s\d{1,2},\s\d{4}\sat\s\d{1,2}:\d{2}(am|pm)).*/, '$1');
console.log(res);

fiddle demo here : http://jsfiddle.net/kq65X/1/

Upvotes: 1

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