I have got:
var myclass = 'moreElements showAddElements-570';
var re = new RegExp('showAddElements\-\d*');
var m = re.exec(myclass);
alert(m[0]);
alert(m[1]);
First alert results in 'showAddElements-', second alert in 'undefined'. I would like to get '570', what I am doing wrong here? If I test it, I get there at least 'showAddElements-570' ... what am I doing wrong here?
Thx for any tipps!
P.s.: I'd like the number only after 'showAddElements-', all other numbers should be omitted..
Simply use the correct regex:
var re = /showAddElements-(\d+)/;
I removed the backslash before the dash (not needed) and added parens around the digits to turn it into a capturing group -- otherwise m[1] would always be undefined.
You need to actually capture the subpattern you want:
/showAddElements-(\d*)/
Note that you don't need to escape - because it has no meaning outside a character class.
Here's some code that works:
var myclass = 'moreElements showAddElements-570';
var re = new RegExp(/showAddElements\-(\d*)/);
var m = re.exec(myclass);
alert(m[1]);
There were two problems with the RegExp line. First problem is that the expression was wrapped with single quotes instead of slashes. This blew my mind the first time I realized what was up, had no clue you could wrap something with slashes. Without these it was just treated as a string intend of an expression.
The second problem is that the there were no () around the number part. You need that to actually "grab" that part.
Here's a working link: http://jsfiddle.net/MvG2C/
You have to add parentheses around the desired class in order to capture it:
var re = new RegExp('showAddElements\-([0-9]*)');
