avoid special characters in javascript code example

Example 1: remove special characters from string javascript

var str = "Hello^# World/";
str.replace(/[^a-zA-Z ]/g, ""); // "Hello World"

Example 2: how to block special characters in javascript

var iChars = "!@#$%^&*()+=-[]\\\';,./{}|\":<>?";

for (var i = 0; i < document.formname.fieldname.value.length; i++) {
    if (iChars.indexOf(document.formname.fieldname.value.charAt(i)) != -1) {
        alert ("Your username has special characters. \nThese are not allowed.\n Please remove them and try again.");
        return false;
    }
}

Example 3: how to block special characters in javascript

var iChars = "!@#$%^&*()+=-[]\\\';,./{}|\":<>?";

for (var i = 0; i < document.formname.fieldname.value.length; i++) {
    if (iChars.indexOf(document.formname.fieldname.value.charAt(i)) != -1) {
        alert ("Your username has special characters. \nThese are not allowed.\n Please remove them and try again.");
        return false;
    }
}