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   amp       -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   lt       -1        Search   val   indexOf   gt       -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   Thanks in advance   Guido

User · Accepted Answer

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.

User · Answer

You are checking whether the string contains all illegal characters  Change the   s to  amp  amp s

User · Answer

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

User · Answer

var specialChars     lt  gt        amp                        -   var check   function string       for i   0  i  lt  specialChars length i             if string indexOf specialChars i    gt  -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

[javascript] jQuery: Check if special characters exists in string

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