regular expression to check if string has only selected special characters in javascript code example

Example: regex to check if string contains special characters javascript

var format = /[ `!@#$%^&*()_+\-=\[\]{};':"\\|,.<>\/?~]/;
//            ^                                       ^   
document.write(format.test("My@string-with(some%text)") + "<br/>");    //true
document.write(format.test("My string with spaces") + "<br/>");        //true 
document.write(format.test("MyStringContainingNoSpecialChars"));       //false