Mxlt 0 Report post Posted July 16, 2018 Hi! I was going through the JavaScript Tutorial but I bumped into this code that got me so confused...if anybody could explain it to me I would really appreciate it! I am specially confused with the prototype thing, and then those weird codes: after the replace. <!DOCTYPE html> <html> <body> <h2>JavaScript String.trim()</h2> <p>IE 8 does not support String.trim(). To trim a string you can use a polyfill.</p> <script> if (!String.prototype.trim) { String.prototype.trim = function () { return this.replace(/^[\s\uFEFF\xA0]+|[\s\uFEFF\xA0]+$/g, ''); }; var str = " Hello World! "; alert(str.trim()); </script> </body> </html> Quote Share this post Link to post Share on other sites
Ingolme 1,008 Report post Posted July 16, 2018 By changing the prototype of a data type, you change every single object of that type. In this example, they are changing the prototype of the String object so that all strings have a trim() method. The trim() method removes spaces from the beginning and end of a string. The code you see in the replace() method /^[\s\uFEFF\xA0]+|[\s\uFEFF\xA0]+$/g is called a regular expression, it is used to do complex manipulations with strings. There is a tutorial page about regular expressions here: https://www.w3schools.com/js/js_regexp.asp 1 1 Quote Share this post Link to post Share on other sites
