Detailed explanation of hyphens in JavaScript_javascript tips

I spent 2 hours at night to use Javascript to process a simple string filtering function. The code is pasted below. It is actually very simple. I just want to remove Filter out.

A very important reason why it takes so much time is that I am not familiar with the character concatenation operation of JavaScript. JS does not support =, so you need to use a=a 'b'. In fact, this problem is very simple when you think about it, but I don't know why it took a lot of time.

Copy code The code is as follows:

function ProcessString(string){
var i= 0;
var leftTagFlag = false
var clearString = new String();//no tag string
alert("string.length = " string.length);
while( i < string.length){
switch(string.charAt(i)){
case '<': leftTagFlag = true;
break;
case '>': leftTagFlag = false;
break;
case '/':
case 'b': if(leftTagFlag)
break;
else clearString.concat( string.charAt(i) );
default: clearString = clearString.concat( string.charAt(i) );
}  
i ;
}