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EduBw
Asked: 2020-05-28 07:25:25 +0800 CST 2020-05-28 07:25:25 +0800 CST

Problems with replaceAll in javascript

  • 772

I want to replace all the characters of the input type text, I have seen on the internet that /g is used, but when I put it, I get an error that it is not "defined" 

  function replaceAllInvalidCharacter(id){
        var characters = ["/","\\", "¿","?","#","<",">","[","]","{","}","%","="];
    var val = document.getElementById(id).value;

    for(var i = 0 ; i < characters.length; i++){
        if (val.indexOf(characters[i]) != -1) {
            val = val.replace(characters[i]/g, '');
        } 
    }
    document.getElementById(id).value = val;
 }

bug ->

Uncaught ReferenceError: g is not defined

How do I make it take all the characters?

For example: e/d/um/o/l/ay stay with edu cool...

javascript

4 Answers

  1. Trying to concatenate /gthere is pointless, as it can only be used with RegExp literals. Therefore you have two options:

    1. Pre-mount all regexp.
    2. Use the constructor of the RegExp class, which receives a string for the regexp and another for the modifiers.

    Examples:

    function replaceAllInvalidCharacter(id){
  var characters = [/\//g,/\\/g, /=/g];
  var val = document.getElementById(id).value;

  for(var i = 0 ; i < characters.length; i++){
    val = val.replace(characters[i], ''); 
  }
  document.getElementById(id).value = val;
 }
 
 replaceAllInvalidCharacter('inp');
    <input id="inp" value="En /un \lug=ar =/\de la Mancha"/>

    function replaceAllInvalidCharacter(id){
  var characters = ["/","\\\\", "¿","\\?","#","<",">","\\[","\\]","{","}","%","="];
  var val = document.getElementById(id).value;

  for(var i = 0 ; i < characters.length; i++){
    val = val.replace(new RegExp(characters[i],'g'), '');
  }
  document.getElementById(id).value = val;
}
 
 replaceAllInvalidCharacter('inp');
    <input id="inp" value="En /un \lug=ar =/\de la Mancha"/>

    As you can see, working with literals is more comfortable (you don't need the double \to escape characters), but in any case you won't be able to use indexof to search first, although it's not necessary.

    • 6
  2. Best Answer

    I think that what you want to do is done with a Regex (Regular Expression) and for what you put it would be the following [/"\\¿?#<>\[\]{}%=]+, being as follows:

    function replaceAllInvalidCharacter(id){
    var characters = /[/"\\¿?#<>\[\]{}%=]+/g;
    var val = document.getElementById(id).value;    
    val = val.replace(characters, '');        
    document.getElementById(id).value = val;
 }

    • 3

  3. It would be enough to go through the collection of invalid characters in an array.map and replace them with ''

    function replaceAllInvalidCharacter(id){
    var characters = ["/","\\", "¿","?","#","<",">","[","]","{","}","%","="];
    var val = document.getElementById(id).value;

    characters.map(function(char){
        val.replace(char, '');
    });

    document.getElementById(id).value = val;
}
    • 2

  4. The problem is that the /g you are trying to use is from a regular expression, but the character value is not.

    To fix it, you have to instantiate a regular expression. Use the following code:

    function replaceAllInvalidCharacter(id){
    var characters = ["/","\\", "¿","?","#","<",">","[","]","{","}","%","="];
    var val = document.getElementById(id).value;

    for(var i = 0 ; i < characters.length; i++){
        if (val.indexOf(characters[i]) != -1) {
            var re = new RegExp(characters[i], "g");
            val = val.replace(re, '');
        } 
    }
    document.getElementById(id).value = val;
}

    For more documentation about regular expressions, https://developer.mozilla.org/en/docs/Web/JavaScript/Reference/Global_Objects/RegExp

    • 1