Question

I want a function which can replace substring in a big string with specific rule.

for example, I want every digit for pageX in the string increase by 10.

function replace(str, increment){}

doreplace("pageX : 100, pageY: 200,......pageX : 120...", 10)

will get "pageX : 110, pageY: 200,......pageX : 130..."

I know that like string.replace(/pageX :/g,someStr) can do replaceAll, but no rule can be applied.
How can I get that?

Answer 1

How about using replace function callback:

var string = "pageX : 100, pageY: 200,......pageX : 120...";
string = string.replace(/(\d+)/g, function(match, contents) {
    return (+contents + 10);
});
console.log(string);

DEMO: http://jsfiddle.net/ytptN/