JavaScript intercepts strings (implemented through substring and supports mixed Chinese and English)_javascript skills

JavaScript intercepts strings (supports mixed Chinese and English)

Copy code The code is as follows:

< script type="text/javascript">
var sub=function(str,n){
var r=/[^x00-xff]/g;
if(str.replace(r, "mm").length<=n){return str;}
var m=Math.floor(n/2);
for(var i=m;iif(str.substr(0,i).replace(r,"mm").length>=n){
return str.substr(0,i) "...";
}
}
return str;
}
alert(sub('String interception Javascript processing summary (Js interception Chinese string summary)',15))

Use js method substring()

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));--------""

Use js method substr()

Copy code The code is as follows:

var str = "0123456789";
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));----------""