如何使用jquery / javascript比较string是否最后有一个回车键？

Question

I have a string value from a user input box. I have to figure out if last char is a enter key (line feed).

Thats the code. Here I am checking if last char has a whitespace. Now I also have to check if last char is enter key (carriage return or line feed). How can i do this?

var txt = $get("<%= txtUserText.ClientID %>");
if (txt.value.substring(txt.value.length -1) !== ' ' || <checkifLastCharIsEnterKey>) 
  //my code to take action

****I don't think i need a keypress or keyup event because this above piece of code is not invoked at the time of user input.**

Answer 1

Well you could use a regular expression:

if (/[\r\n]$/.test(txt)) { /* it has a newline at the end */ }

If you want to get rid of it:

txt = txt.replace(/[\r\n]$/, '');

If you want to get rid of all "whitespace" at the end of the string:

txt = txt.replace(/\s*$/, '');

Answer 2

You can use a regular expression:

if(/\s$/.test(txt.value))

This will check whether the last character is any whitespace character (including the tab and newline characters).

EDIT :

To check for newlines separately:

if(/\r|\n$/.test(txt.value)) {
    //Newline
} else if(/\s$/.test(txt.value)) {
    //Any other whitespace character
}