js string interception related knowledge

Interception of a digital string

　　1, using the parseInt ()

　　var str = "4500 membered"; 
　　var NUM = the parseInt (STR); 
　　the console.log (NUM); // 4500 
　　the parseInt () method parameter can have a non-numeric string, can be as long as the number before the string

　　2, using regular

　　var str = "price 4500 yuan"; 
　　var NUM = s.replace does (/ [^ 0-9] / IG, ""); 
　　Alert (NUM); // 4500

Interception string

　　1, using the split ()

　　Function: using the specified delimiter, cutting string, and stores the array　　　var STR = "A, B, C, D, E, F"; 
　　var str.split ARR = ( ","); 
　　the console.log (arr); // [ "a ", "b", "c", "d", "e", "f"]　

　　2, using the join ()

　　Function: using their specified delimiter, will be merged into a string array 
　　var ARR = [A, B, C, D, E, F]; 
　　var = arr.join STR ( "|"); 
　　the console.log (STR ); // "a | b | c | d | e | f"

　　3, using substring ()

　　Function: the specified field can be intercepted 
　　var STR = "abcdef"; 
　　var str2 str.substring = (0,3); 
　　the console.log (str2); // "ABCD"

　　4, using the indexOf ()

　　Function: Returns a string that matches the index of the first character of the substring 
　　var STR = "Hello Web"; 
　　var str.indexOf S1 = ( "LL"); // 2 
　　var str.indexOf S2 = ( "J "); // returns -1 if no match

　   5, using substr ()

　　Function: Returns a string length specified beginning from the specified location 
　　var STR = "Hello Web"; 
　　var str.substr S1 = (0,4); // Hell 
　　var str.substr S2 = (. 3); // "LO web "