Use javascript to implement the function of intercepting strings containing Chinese processing_javascript skills

1.substring method
Definition and usage
The substring method is used to extract characters between two specified subscripts in a string.
Syntax
stringObject.substring(start,stop)
Parameter Description
start Required. A nonnegative integer that specifies the position in stringObject of the first character of the substring to be extracted.
stop optional. A nonnegative integer that is one position in the stringObject that is one more than the last character of the substring to be extracted. If this parameter is omitted, the returned substring will go to the end of the string.
Return value
A new string value containing a substring of stringObject, whose content is all characters from start to stop-1, and its length is stop minus start.
Explanation
The substring returned by the substring method includes the characters at start, but does not include the characters at end.
If start and end are equal, then this method returns an empty string (that is, a string of length 0).
If start is greater than end, then this method will swap the two parameters before extracting the substring.
If start or end is negative, then it will be replaced by 0.

2.substr method
Definition and usage
The substr method is used to return a substring of specified length starting from the specified position.
Syntax
stringObject.substr(start [, length])
Parameter Description
start Required. The starting position of the desired substring. The first character in the string has index 0.
length optional. The number of characters that should be included in the returned substring.
Description
If length is 0 or negative, an empty string will be returned.
If this parameter is not specified, the substring will be continued to the end of stringObject.
Example:

Copy code The code is as follows:

var str = "0123456789";
alert(str.substring(0));------------"0123456789"
alert(str.substring(5));--- ----------"56789"
alert(str.substring(10));-----------""
alert(str.substring(12)) ;-----------""
alert(str.substring(-5));-----------"0123456789"
alert(str.substring (-10));----------"0123456789"
alert(str.substring(-12));----------"0123456789"
alert (str.substring(0,5));----------"01234"
alert(str.substring(0,10));----------"0123456789 "
alert(str.substring(0,12));---------"0123456789"
alert(str.substring(2,0));------- ---"01"
alert(str.substring(2,2));----------""
alert(str.substring(2,5));-- --------"234"
alert(str.substring(2,12));---------"23456789"
alert(str.substring(2,- 2));---------"01"
alert(str.substring(-1,5));---------"01234"
alert(str .substring(-1,-5));--------""
alert(str.substr(0));---------------" 0123456789"
alert(str.substr(5));---------------"56789"
alert(str.substr(10));---- ----------""
alert(str.substr(12));--------------""
alert(str.substr( -5));--------------"0123456789"
alert(str.substr(-10));-------------" 0123456789"
alert(str.substr(-12));-------------"0123456789"
alert(str.substr(0,5));--- ----------"01234"
alert(str.substr(0,10));------------"0123456789"
alert(str. substr(0,12));----------------"0123456789"
alert(str.substr(2,0));------------ -""
alert(str.substr(2,2));-------------"23"
alert(str.substr(2,5));- ------------"23456"
alert(str.substr(2,12));------------"23456789"
alert( str.substr(2,-2));----------------""
alert(str.substr(-1,5));--------- ---"01234"
alert(str.substr(-1,-5));-----------""

3. indexOf　
Returns the character position of the first substring occurrence in the String object.
strObj.indexOf(subString[, startIndex])
　Parameters
　strObj
　Required. String object or literal.
subString
Required. The substring to find in the String object.
starIndex
Optional. This integer value indicates the index within the String object at which to begin the search. If omitted, the search is from the beginning of the string.
　Description
　The indexOf method returns an integer value indicating the starting position of the substring within the String object. If the substring is not found, -1 is returned.
If startindex is negative, startindex is treated as zero. If it is greater than the largest character position index, it is treated as the largest possible index.
Execute the search from left to right. Otherwise, the method is the same as lastIndexOf.
　Example
　The following example illustrates the usage of the indexOf method.

Copy code The code is as follows:

function IndexDemo(str2){
var str1 = "BABEBIBOBUBABEBIBOBU"
var s = str1.indexOf(str2);
return(s);
}

Copy code The code is as follows:

/* 2007-11-28 XuJian * /
//Intercept string including Chinese processing
//(String, length, increase...)
function subString(str, len, hasDot)
{
var newLength = 0 ;
var newStr = "";
var chineseRegex = /[^x00-xff]/g;
var singleChar = "";
var strLength = str.replace(chineseRegex,"** ").length;
for(var i = 0;i {
singleChar = str.charAt(i).toString();
if(singleChar.match (chineseRegex) != null)
                                                                 newLength ;
} }
if(newLength > len)
                                                                             ; len)
{
newStr = ".. .";
}
return newStr;
}










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