jQuery: Check if special characters exists in string

Question

I know this question is asked more often here on Stack, but I can't seem to get a straight answer out of the questions already posted.

I need to check if all special characters (except -) are in a string, if so, then give the user an alert.

What I have so far is this:

if($('#Search').val().indexOf('@') == -1 || $('#Search').val().indexOf('#') == -1 || $('#Search').val().indexOf('$') == -1 || $('#Search').val().indexOf('%') == -1 || $('#Search').val().indexOf('^') == -1 || $('#Search').val().indexOf('&') == -1 || $('#Search').val().indexOf('*') == -1 || $('#Search').val().indexOf('(') == -1 || $('#Search').val().indexOf(')') == -1 || $('#Search').val().indexOf('_') == -1 || $('#Search').val().indexOf('\'') == -1 || $('#Search').val().indexOf('\"') == -1 || $('#Search').val().indexOf('\\') == -1 || $('#Search').val().indexOf('|') == -1 || $('#Search').val().indexOf('?') == -1 || $('#Search').val().indexOf('/') == -1 || $('#Search').val().indexOf(':') == -1 || $('#Search').val().indexOf(';') == -1 || $('#Search').val().indexOf('!') == -1 || $('#Search').val().indexOf('~') == -1 || $('#Search').val().indexOf('`') == -1 || $('#Search').val().indexOf(',') == -1 || $('#Search').val().indexOf('.') == -1 || $('#Search').val().indexOf('<') == -1 || $('#Search').val().indexOf('>') == -1 || $('#Search').val().indexOf('{') == -1 || $('#Search').val().indexOf('}') == -1 || $('#Search').val().indexOf('[') == -1 || $('#Search').val().indexOf(']') == -1 || $('#Search').val().indexOf('+') == -1 || $('#Search').val().indexOf('=') == -1)
{
   // Code that needs to execute when none of the above is in the string
}
else
{
  alert('Your search string contains illegal characters.');
}

But this doesn't seem to work. Can anyone help me on this matter?

You need to use a regular expression here instead of a bazillion separate conditions. And you **definitely** have to say how exactly it "doesn't seem to work". — Jon, Dec 12 '12 at 12:48
See this may be help you http://stackoverflow.com/questions/10505772/checking-for-any-occurrence-of-special-characters-with-jquery — Hkachhia, Dec 12 '12 at 12:53

bfavaretto · Accepted Answer · 2012-12-12T13:47:47.973

98

If you really want to check for all those special characters, it's easier to use a regular expression:

var str = $('#Search').val();
if(/^[a-zA-Z0-9- ]*$/.test(str) == false) {
    alert('Your search string contains illegal characters.');
}

The above will only allow strings consisting entirely of characters on the ranges a-z, A-Z, 0-9, plus the hyphen an space characters. A string containing any other character will cause the alert.

edited Dec 12 '12 at 13:47

answered Dec 12 '12 at 12:50

bfavaretto

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Added a short explanation. The downside is that it won't allow international characters like `é` and `ñ`, but if you don't need to allow them I believe it's the way to go. – bfavaretto Dec 12 '12 at 13:30
It works, even with the international characters ;) Thanks again! – Guido Visser Dec 12 '12 at 15:14
2

This fails for international characters (chinese, arabic etc). I wouldn't use it. It doesn't look for special characters like anton's example. – Marvin Saldinger Apr 23 '14 at 11:34
Why don't we write `/[^a-zA-Z0-9- ]*$/` instead of `/^[a-zA-Z0-9- ]*$/`? – Alston Jan 27 '15 at 07:55
@Stallman The meaning is different. Inside the brackets, the `^` negates the list instead of defining the beginning of the string. – bfavaretto Jan 27 '15 at 14:49
@bfavaretto what if characters like ☺■☻♣♦♠☼♫♪↕§ these appears on my copied text and I want to validate this on pasting to a text field – tvshajeer Mar 18 '15 at 06:01
It seems this example doesn't invalidate whitespace. To do so, use /^[a-zA-Z0-9-]*$/ – Jihoon Baek Sep 20 '16 at 21:42

score 23 · Answer 2 · edited Dec 08 '15 at 05:13

var specialChars = "<>@!#$%^&*()_+[]{}?:;|'\"\\,./~`-="
var check = function(string){
    for(i = 0; i < specialChars.length;i++){
        if(string.indexOf(specialChars[i]) > -1){
            return true
        }
    }
    return false;
}

if(check($('#Search').val()) == false){
    // Code that needs to execute when none of the above is in the string
}else{
    alert('Your search string contains illegal characters.');
}

score 6 · Answer 3 · answered Dec 12 '12 at 13:24

6

You could also use the whitelist method -

var str = $('#Search').val();
var regex = /[^\w\s]/gi;

if(regex.test(str) == true) {
    alert('Your search string contains illegal characters.');
}

The regex in this example is digits, word characters, underscores (\w) and whitespace (\s). The caret (^) indicates that we are to look for everything that is not in our regex, so look for things that are not word characters, underscores, digits and whitespace.

answered Dec 12 '12 at 13:24

Jay Blanchard

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4

This fails for international characters(chinese, arabic etc).I wouldn't use it. – Marvin Saldinger Apr 23 '14 at 11:31
`== true`? Wouldn't `if(regex.test(str)) { [...] }` suffice? – scniro Oct 23 '15 at 00:48
Of course it would @scniro. I just put the entire equation for clarity sake. – Jay Blanchard Oct 23 '15 at 11:36

score 2 · Answer 4 · answered Dec 12 '12 at 12:49

2

You are checking whether the string contains all illegal characters. Change the ||s to &&s.

answered Dec 12 '12 at 12:49

JJJ

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jQuery: Check if special characters exists in string

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