Detailed explanation on the use of replace of String object in js_javascript skills

Today when I was reading the source code stringH of Qwrap, there was a

copy code The code is as follows:

format: function(s, arg0) {
var args = arguments;
return s.replace(/{(d )}/ig, function(a, b) {
return args[(b | 0) 1] || '';
});
}

The way to use it is:
alert(format("{0} love {1}.", 'I','You'))//I love you The implementation of
format mainly uses the replace method of the String object:

replace: Returns the characters after text replacement according to the regular expression Copy of string.

1. Commonly used replacement

Copy code The code is as follows:

function ReplaceDemo(){
var r, re; // Declare variables.
var ss = "The man hit the ball with the bat.n";
ss = "while the fielder caught the ball with the glove.";
re = /The/g; // Create Regular expression pattern.
r = ss.replace(re, "A"); // Replace "The" with "A".
return(r); // Return the replaced string.
}
ReplaceDemo(); //A man hit the ball with the bat. while the fielder caught the ball with the glove.

2. Subexpression in replacement pattern

Copy code The code is as follows:

function ReplaceDemo(){
var r, re ; // Declare variables.
var ss = "The rain in Spain falls mainly in the plain.";
re = /(S )(s )(S )/g; // Create a regular expression pattern.
r = ss.replace(re, "$3$2$1"); // Swap each pair of words.
return(r); // Return the result string.
}
document.write(ReplaceDemo()); //rain The Spain in mainly falls the in plain.

Matching regular items: The rain, in Spain, falls mainly ,in the;Execute ss.replace(re, "$3$2$1") operation to complete the exchange of word positions

$1 matches the first (S)

$2 matches (s )

$3 matches the second (S )

3.replace when the second parameter is function

Copy code The code is as follows:

function f2c(s){
var test = /(d (.d*)?)Fb/ g; //Initialization mode.
return(s.replace(test,function($0,$1,$2){return((($1-32)) "C");}));
}
f2c("Water boils at 212F 3F .2F 2.2F .2");//Water boils at 180C -29C .-30C -29.8C .2

$0 matches 212F,3F,.2F,2.2F
$1 matches 212,3,.2,2.2
$2 matches the last .2