js trim function, space removal function and regular collection_javascript skills

But if the project does not use a framework such as jQuery, js itself does not have such a function, and we have to write such a function ourselves. The following is the specific implementation of the function:

Copy the code The code is as follows:

//For users to call
function trim(s){
return trimRight(trimLeft(s));
}
//Remove the left whitespace
function trimLeft(s){
if(s == null) {
return "";
}
var whitespace = new String(" tnr");
var str = new String(s);
if (whitespace.indexOf(str.charAt(0)) != -1) {
var j=0, i = str.length;
while (j < i && whitespace.indexOf(str.charAt(j)) != -1){
j ;
}
str = str.substring (j, i);
}
return str;
}
//Remove the blank space on the right
function trimRight(s){
if(s == null) return " ";
var whitespace = new String(" tnr");
var str = new String(s);
if (whitespace.indexOf(str.charAt(str.length-1)) != -1){
var i = str.length - 1;
while (i >= 0 && whitespace.indexOf(str.charAt(i)) != -1){
i-- ;
}
str = str.substring(0, i 1);
}
return str;
}

When using, just call the trim function That’s it.
The following is the implementation method using regular expressions:

Copy the code The code is as follows:

< ;SCRIPT LANGUAGE="JavaScript">

Because of the editor problem, the spaces have been replaced in the above code, so Please pay attention to adding spaces and test.