Code _ javascript

I can see that the project uses the js array split method to format the query string. Why cannot I use regular expressions? What is the performance? If you are interested, you can study it. You can see that the project uses the js array split method to format the query string. Why can't you use regular expressions? What is the performance? The following code is available:

The Code is as follows:

Var url = 'www .baidu.com? A = 123 & B = 456 & c = 789 & e = dfsdfsdfsdfsdfsdf & f = 46545454545454785 & g = e23232dsfvdfvdf ';
/**
* Format the query string (regular expression)
* @ Param url
* @ Return {Object} formatted json Object
*/
Function formatUrl (url ){
Var reg = /(? :[? &] +) ([^ &] +) = ([^ &] +)/G;
Var data = {};
Function fn (str, pro, value ){
Data [decodeURIComponent (pro)] = decodeURIComponent (value );
}
Url. replace (reg, fn );
Return data;
}
/**
* Format the query string (Array Implementation)
* @ Param url
* @ Return {Object} formatted json Object
*/
Function formatUrl2 (url ){
Url = url. replace (/.*\? /,'');
Var args = {},
Items = url. length? Url. split ("&"): []
, Item = null
, I = 0
, Len = items. length;
For (I = 0; I Item = items [I]. split ("= ");
Args [decodeURIComponent (item [0])] = decodeURIComponent (item [1]);
}
Return args;
}
Var startTime = new Date ();
For (var I = 0; I <1000000; I ++ ){
FormatUrl2 (url );
}
Console. log ('formaturl2 ', (new Date ()-startTime); // formatUrl2 12138
StartTime = new Date ();
For (var I = 0; I <1000000; I ++ ){
FormatUrl (url );
}
Console. log ('formaturl', (new Date ()-startTime); // formatUrl 12537

The test browser is chrme 25; the regular expression function is slower than the function implemented by the array ....). But fortunately, it takes only 1 million seconds to repeat the execution for 0.4 times.