AS3 JS Regular Expression Reverse reference (backreference) _ Regular expression

AS3 Code:

var str = ""; 
var reg =/(\d{}) \/gx; 
\ is a reverse grouping that represents the same matching result character as the previous group. such as \d{} match, then \ can only be matched, 
var first=str.match (reg); 
Match (), returns an object, if Reg has global attribute G, the object's numeric index is the exact match character, 
//If there is no global attribute G, the index is the first exact match character, and the other indexes are matched characters for each group for 
{ 
Trace (first property name: "+key +", Value: "+ First[key]) 
}/ 
* 
output 
First property name:, Value: 
First property name:, Value: 
*/

JS Code

<script language= "JavaScript" > 
var str = ""; 
var reg =/(\d{}) \/gx; 
\ is a reverse grouping that represents the same matching result character as the previous group. such as \d{} match, then \ can only be matched, 
var first=str.match (reg); 
Match (), returns an object, if Reg has global attribute G, the object's numeric index is the exact match character, 
//If there is no global attribute G, the index is the first exact match character, and the other indexes are matched characters for each group in order 
(Var key in First) 
{ 
document.write ("+key +", Value: "+ First[key]") 
} 
</script> 
<!-- 
output.
First property name:, Value: 
First property name:, Value: 

More complex reverse references:

Here is a simple keyword search highlighting regular expression usage.

AS3

var str = ""; 
var reg =/(\d{}) \/gx; 
var first=str.replace (Reg, "<font color=red>$$</font>"); 
Output <font Color=red>$</font><font color=red>$</font>. The 
//replace () function is to replace the matching string with the corresponding field. 
//Note the $ reverse represents the group \d{} in the first bracket of Reg, and the $ is shown directly, indicating that the regular expression only recognizes parentheses as grouping and does not recognize/identify as the second group 

Js

<script language= "JavaScript" > 
var str = ""; 
var reg =/(\d{}) \/gx; 
var first=str.replace (Reg, "<font color=red>$$</font>"); 
Output <font Color=red>$</font><font color=red>$</font>. The 
//replace () function is to replace the matching string with the corresponding field. 
//Note the $ reverse represents the group \d{} in the first bracket of Reg, and the $ is shown directly, indicating that the regular expression only recognizes parentheses as a grouping and does not recognize/identify as the second grouping 
document.write (a); 

The above content is small to introduce the AS3 JS regular expression of the reverse reference (backreference), I hope to help you!