Description
This page will show you how to retrieve with Javascript an inline property value defined with the style attribute
The How to will retrieve the 20px of the font-size from the below HTML code
<p style="font-size: 20px">Foo bar</p>
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Bird's-eye view solution
This howto will use the element.style object of a javascript element. This is where the inline style definition is stored.
If the property is defined in a style sheet, the property will not be present in the element.style object and will report an empty string.
How to Steps
Define a css stylesheet
We define a stylesheet to show that the value of element.style.fontSize is not defined in this case
.sheet { font-size: 15px }
Create the HTML page
- with an inline style
<p style="font-size: 20px">A p element with the font-size defined inline</p>
- with a class defined in the sylesheet
<p class="sheet">A p element with the font-size defined by a stylesheet</p>
Retrieve the elements with Javascript
allP = document.querySelectorAll("p");
Output the value of element.style.fontSize for each element
- The first p element will have a element.style.fontSize
console.log("The first p with an inline definition has a fontSize property of "+allP.item(0).style.fontSize);
- The second will have not
console.log("The second p with a stylesheet definition has an undefined fontSize property "+(typeof allP.item(1).style.fontSize == 'undefined'));