Show/Hide text JavaScript error -

this example show/hide text http://codepen.io/svinkle/pen/aqwdu intend adapt in website , how fix code not repeat first lines of paragraph? in example text begins "lorem ipsum dolor sit amet, consectetur adipiscing elit. vestibulum facilisnim wanted molestie", has been repeated before 3 points ( ... ) how fix it?

// select text areas var textarea = document.queryselectorall('[data-js=content]'),     maxtext = 100;  // each one... [].foreach.call( textarea, function( el ) {  var textarealength = el.innerhtml.length, teasertext = el.innerhtml.substr(0, 100), fulltext = el.innerhtml, showteaser = false;      // check see if text length more // max if (textarealength >= maxtext) { // set flag showteaser = true;  // set teaser text   el.innerhtml = teasertext; el.innerhtml += el.innerhtml + '...';  // create button var button = document.createelement('button'); button.innerhtml = 'show more'; button.classlist.add('button'); el.appendchild(button);  // button click event button.onclick = function () {   if (showteaser === true) {     // update flag     showteaser = false;      // update button text     this.innerhtml = 'show less';      // show full text     el.innerhtml = fulltext;      // re-append button     el.appendchild(this);   } else {     // update flag     showteaser = true;      // update button text     this.innerhtml = 'show more';      // show teaser text     el.innerhtml = teasertext;     el.innerhtml += el.innerhtml + '...';      // re-append button     el.appendchild(this);   }   return false; }; } else {  // show full text el.innerhtml = fulltext; }     }); 

el.innerhtml += el.innerhtml + '...'; 

the error in above line.you're adding el.innerhtml twice. @ first adding ... , adding because of shorthand += operator.

it should just

el.innerhtml += '...'; 

it's present in multiple places, may need edit those.