Ellipsis mediante JavaScript

ellipsis.js

    var ellipsisId= 'ellipsis_test_element';
    var ellipsisElement= null;
    function insertEllipsisElement(){
        if( !ellipsisElement){
            ellipsisElement= document.createElement( 'div');
            ellipsisElement.id= ellipsisId;
            document.body.appendChild( ellipsisElement);
        }
    }
    
    function substring( text, i, f){
        return text.substr( i, f);
    }
    
    this.autoEllipseText=function(element, text, width)
    {
        insertEllipsisElement();
       var inSpan= document.createElement( 'span');
       inSpan.id= "ellipsisSpan";
       inSpan.className= element.className;
       inSpan.style.whiteSpace="nowrap";
       inSpan.style.visibility="hidden";
       var returnText= text;
       
       ellipsisElement.appendChild( inSpan);
       inSpan.innerHTML = text;
       if(inSpan.offsetWidth > width)
       {
          var i = 0;
          inSpan.innerHTML = '';

          returnText= binarySearch( inSpan, text, width);
          // returnText= bruteForceSearch( inSpan, text, width);
          
       }
       ellipsisElement.removeChild( inSpan);
       return returnText;
    }
    
    function bruteForceSearch( inSpan, text, width){
        // Version of the algorithm with brute force search
        var i= 0;
        while( inSpan.offsetWidth < (width) && i < text.length)
        {
            i++; 
           inSpan.innerHTML = text.substr(0,i) + '&hellip;';
        } 
        return text.substr( 0, i-1) + '&hellip'; 
        
    }
    
    function binarySearch( inSpan, text, width){
        var left= 0;
        var right= text.length;
        var c= right;
        // Version of the algorithm with binary search
        while ((c = Math.floor((right + left) / 2)) > left) {
            inSpan.innerHTML = text.substr(0, c) + '&hellip;';
            if ( inSpan.offsetWidth > width) right = c;
            else left = c;
        }
        return text.substr( 0, c) + '&hellip'; 
    }