increment disminir

by femfoyou

HTML

<script>
function inc_count(valor){
    res = document.getElementById("output");
    res.value = parseInt(res.value)+1;
}
</script>
 
<input type="text" value="0" id="output"/>
<span id="valor">0</span>

<a href="javascript:inc_count()">Incrementar</a>
<a href="javascript:inc_count()">Disminiuir</a>


<span class="sp1" id="button2" onclick="changeFontSize(this)">a-</span>
<span class="sp2" id="button1" onclick="changeFontSize(this)">a+</span>

JavaScript

function changeFontSize(target) {
  var demo = document.getElementById("output");
  var cifra = document.getElementById("valor");
  var fontSize;

  if (computedStyle) {
    fontSize = parseFloat(computedStyle && computedStyle.fontSize);
    
  if (target == document.getElementById("button1")) { fontSize += 5; } 
  else if (target == document.getElementById("button2")) { fontSize -= 5;}
      
      demo.value = fontSize;
  }

//  localStorage.setItem('myFontSize', fontSize);
//  p.value = localStorage.getItem('myFontSize');
  cifra.innerHTML = demo.value;
}

cifra.innerHTML = demo.value;