JS Common API method

The commonly used Api:api of string objects refers to the application programming interface, which is actually some pre-programmed method.

The CharAt () method returns the character at the specified position. Stringobject.charat (Index)

The IndexOf () method returns the position of the first occurrence of a specified string value in a string. Stringobject.indexof (Searchvalue, Fromindex)

The substring () method is used to extract the character of a string intermediary between two specified subscripts. Stringobject.substring (Start, stop)

The slice () method extracts a portion of a string and returns the extracted part with a new string. Stringobject.slice (start, end)

The split () method is used to split a string into an array of strings. Stringobject.split (separator)

The replace () method is used to replace some characters in a string with some other characters stringobject.replace (REGEXP/SUBSTR, replacement)

            varStr= "Month white wind green all the Yi Xing Zhuang think fly, want to on the blue sky to embrace the moon"varNstr=str.charat (8) document.write ("The role of Charat" +nstr+ "<br>")                                varNstr1=str.indexof ("green");//the first occurrence of the character, from left to right to start the query. document.write ("The Role of IndexOf" +nstr1+ "<br>")                varNstr2=str.lastindexof ("green");//the first occurrence of the character, from right to left to start the query. LastIndexOf note the case of lettersdocument.write ("The Role of LastIndexOf" +nstr2+ "<br>")                varNstr3=str.substring (8)//Intercept from an element labeled eight, and intercept to the enddocument.write ("The Role of substring" +nstr3+ "<br>")                                varNstr4=str.substring (8,13)                //The element starting from subscript Eight is intercepted, and the element between 8 and 12 is truncated to the element labeled 13, including 8 and.document.write ("The Role of substring" +nstr4+ "<br>")                                varNstr4=str.substring ( -13,13)                //negative numbers cannot be taken, and negative numbers will be truncated from 0 to the element labeled 13. document.write ("The Role of substring" +nstr4+ "<br>")                                varNstr5=str.substr (4,7)//starting with the element subscript 4, the element containing the subscript 4 is truncated seven characters backward. That is, a string of length 7 is intercepted. document.write ("The Role of Substr" +nstr5+ "<br>")                                varNstr6=str.substr ( -7,7)//Seven characters are truncated from the bottom of the 7th element, including the bottom seventh element. That is, a string of length 7 is intercepted. document.write ("The Role of Substr" +nstr6+ "<br>")                                varNstr7=str.substr ( -9,-7)//a string of length 7 is intercepted starting from the bottom 9th element. However, the length cannot be negative and will be calculated as length 0, so it will not take effect. document.write ("substr role" +nstr7+ "does not take effect" + "<br>")                                varNstr8=str.slice (4,11)//The element with subscript 11 is not included until the element with subscript 4 is truncated to the element labeled 11. document.write ("The Role of Slice" +nstr8+ "<br>")                                varNstr9=str.slice ( -7,-5)//The bottom seventh element intercepts an element that follows the seventh element, and cannot be preceded by the seventh element. document.write ("The Role of Slice" +nstr9+ "<br>")                                varNstr10=str.split ("Green") document.write ("The role of Split" +nstr10+ "<br>")                                varNstr11=str.replace ("Qing", "Hua")//only the first green word found is replaced.document.write ("Function of Replace" +nstr11+ "<br>")

JS Common API method