CODEWITHSUNDEEP
regex
ifelse
ifelse

Reputation: 319

Reg expression validate / \ # & characters

I've been learning how Regular expressions work, which is very tricky for me. I would like to validate this chars below from input field. Basically if string contains any of these characters, alert('bad chars')

  1. /
  2. \
  3. #
  4. &

I found this code, but when I change it around doesn't seem to work. How can I alter this code to meet my needs?

var str = $(this).val();
if(/^[a-zA-Z0-9- ]*$/.test(str) == false) {
    alert('bad');
    return false;
} else {
    alert('good');
}

Upvotes: 1

Views: 114

Answers (2)

fourpastmidnight
fourpastmidnight

Reputation: 4234

You could just try the following:

if("/[\\/#&]/".test(str) == true) {
    alert('bad');
    return false;
} else {
    alert('good');
}

NOTE: I'm not 100% on what characters need to be escaped in JavaScript vs. .NET regular expressions, but basically, I'm saying if your string contains any of the characters \, /, # or &, then alert 'bad'.

Upvotes: 1

h2ooooooo
h2ooooooo

Reputation: 39532

/^[a-zA-Z0-9- ]*$/ means the following:

  • ^ the string MUST start here
  • [a-zA-Z0-9- ] a letter between a and z upper or lower case, a number between 0 and 9, dashes (-) and spaces.
  • * repeated 0 or more times
  • $ the string must end here.

In the case of "any character but" you can use ^ like so: /^[^\/\\#&]*$/. If this matches true, then it doesn't have any of those characters. ^ right after a [ means match anything that isn't the following.

.

Upvotes: 1

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