Problem with Javascript onclick change font size

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Hi everyone, I've got a problem with changing the font-size. I've tried a few methods like this :

function resizeText(multiplier) {
if (document.body.style.fontSize == "") {
document.body.style.fontSize = "1.0em";
}
document.body.style.fontSize = parseFloat(document.body.style.fontSize) + (multiplier * 0.2) + "em";
}
but it didn't work because I'm working on a website that's been made by professionnals and they didn't use em but the values xx-small, small, large...

This works :

function resizeText(multiplier) {
if (document.body.style.fontSize == "") {

document.body.style.fontSize = "small";
}
}

So I started doing strange stuff like this :

function resizeText(multiplier){

var tab = ["xx-small", "x-small", "small", "medium", "large"," x-large", "xx-large"];

if (document.body.style.fontSize == "") {

switch(tab){
case 'xx-small':
document.body.style.fontSize = "x-small";
break;
case 'x-small':
document.body.style.fontSize = "small";
break;

and so on...

}
}

The only thing that worked in my switch was the default value I put to the font-size.

Then I don't think that putting an array inside a switch is a good idea, I've been thinking about looping or using if/else but somehow I just can't find the answer. I keep doing strange stuff. So if someone could guide me in the right direction, I'dd be gratefull.

Now I've done this, doesn't work either :

<script type="text/javascript">// <![CDATA[

function resizeText(multiplier) {
var tab = ["xx-small", "x-small", "small", "medium", "large", "x-large", "xx-large"];

if (document.body.style.fontSize === tab[0]) {

document.body.style.fontSize = tab[1];
}
else if (document.body.style.fontSize === tab[1])
{
document.body.style.fontSize = tab[2];
}
else if (document.body.style.fontSize === tab[2])
{
document.body.style.fontSize = tab[3];
}
else if (document.body.style.fontSize === tab[3])
{
document.body.style.fontSize = tab[4];
}
else if (document.body.style.fontSize === tab[4])
{
document.body.style.fontSize = tab[5];
}
else if (document.body.style.fontSize === tab[5])
{
document.body.style.fontSize = tab[6];
}
}
// </script>

Posted 4-Jun-15 22:51pm

Member 11492079

Updated 4-Jun-15 23:56pm

v6

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2 solutions

Solution 1

you can use jQuery:

$("body").css("font-size")

here is an example

http://codepen.io/anon/pen/WvjNjN[^]

Posted 5-Jun-15 2:10am

xszaboj

Comments

Member 11492079 5-Jun-15 8:28am

I haven't learned jQuery yet, but what I'm trying to achieve is to create 2 buttons A+ and A- so that people just have to click on it so they can read at the font-size they want. The website is for elder people, I'm trying to imagine myself in their position :) .

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Member 11492079 · Accepted Answer · 2015-06-05T02:37:00

I've found it myself but thanks anyway for those who tried to help :) :

C#

<script type="text/javascript">// <![CDATA[
var tab = ["xx-small", "x-small", "small", "medium", "large", "x-large", "xx-large"];

document.body.style.fontSize = tab[0];
function resizeText(multiplier) {

 if (document.body.style.fontSize == tab[0]) {

document.body.style.fontSize = tab[1];
}
else if (document.body.style.fontSize == tab[1])
{
document.body.style.fontSize = tab[2];
}
else if (document.body.style.fontSize == tab[2])
{
document.body.style.fontSize = tab[3];
}
else if (document.body.style.fontSize == tab[3])
{
document.body.style.fontSize = tab[4];
}
else if (document.body.style.fontSize == tab[4])
{
document.body.style.fontSize = tab[5];
}
else if (document.body.style.fontSize == tab[5])
{
document.body.style.fontSize = tab[6];
}
}
// ]]></script><p><button onclick="resizeText(1)">+</button>