How to change div background color on button click?

Question

I can change the background color Red, Blue, as well as Green, but when I click the Reset button I get an error in Chrome(browser):

btnReset is not a function,

How to make all div blank when I click Reset button?

 function btnRed() { document.getElementById("Div1").style.backgroundColor="Red"; } function btnGreen() { document.getElementById("Div2").style.backgroundColor="Green"; } function btnBlue() { document.getElementById("Div3").style.backgroundColor="Blue"; } function btnReset() { document.getElementById("Div1").style.backgroundColor="Black"; document.getElementById("Div2").style.backgroundColor="white"; document.getElementById("Div3").style.backgroundColor="white"; }

 #Div1 { z-index: -2; border: 1px solid black; height: 300px; width: 400px; } #Div2 { z-index: -1; border: 1px solid black; width: 300px; height: 200px; margin: 50px 0 0 50px; } #Div3 { border: 1px solid black; width: 200px; height: 150px; margin: 23px 0 0 47px; } #DivBtn { margin-top: 30px; }

 <div id="Div1"> <div id="Div2"> <div id="Div3"> </div> </div> </div> <div id="DivBtn"> <input type="button" id="btnR" value="Red" onclick="btnRed();"> &nbsp;&nbsp; <input type="button" id="btnG" value="Green" onclick="btnGreen();">&nbsp;&nbsp; <input type="button" id="btnB" value="Blue" onclick="btnBlue();">&nbsp;&nbsp; <input type="button" id="btnReset" value="Reset" onclick="btnReset()"> </div>

Answer 1

Be careful when you're using id on the html tags, because it makes an automatic var declaration using the id . So, you're overriding the btnReset function with the btnReset pointing to the <input> .

Solution 1: change the id="btnReset" or the function btnReset() name!

Solution 2: move your <script> to the end of the document (just before the </body> end tag, so your function overrides the automatic declarated var.

Additional info: http://www.2ality.com/2012/08/ids-are-global.html

Answer 2

function btnRed() {
  document.getElementById("Div1").style.backgroundColor="Red";
}
function btnGreen() {
  document.getElementById("Div1").style.backgroundColor="Green";
}
function btnBlue() {
  document.getElementById("Div1").style.backgroundColor="Blue";
}
function btnReset() {
  document.getElementById("Div1").style.backgroundColor="Black";
  document.getElementById("Div1").style.backgroundColor="white";
  document.getElementById("Div1").style.backgroundColor="white";
}

#Div1
{ 
  border: 1px solid black;
  height: 300px;
  width: 400px;
}




<div id="Div1">
  <div id="Div2">
    <div id="Div3">

    </div>
  </div>
</div>

<div id="DivBtn"> <input type="button" id="btnR" value="Red" onclick="btnRed();"> &nbsp;&nbsp;
  <input type="button" id="btnG" value="Green" onclick="btnGreen();">&nbsp;&nbsp;
  <input type="button" id="btnB" value="Blue" onclick="btnBlue();">&nbsp;&nbsp;
  <input type="button" id="btnReset" value="Reset" onclick="btnReset()">
</div>