Javascript公式，用于根据原始宽度设置图像宽度，但以百分比表示

Question

This seems basic but i can't wrap my head around it.Honest ain't got no clue but what i need is set the image width in percentage just like in css file but this time around i wonna know the method or technique used to do that.

Example..

//I have tried this but it didn't work
//var image_width_from_server=(the_img_width_from_php);

//image_width_from_server=image_width_from_server/$(parent).width()*90


//Now the result i get from the console does not match the browser set width of the image's p-ercentage width.

#parent{
width:250px;
height:250px;
background:deepskyblue;
border:5px;
}

#parent img{
width:90%;/**Now how can i do this in javaScript..?*/
height:auto;
}


/**Please note that direct css code won't help.
I need a way in javaScript to set the image's width using percentage but also basing on both the image's width size and the parent width size too.
*/

<div id='parent'>
  <img src='https://i.vimeocdn.com/video/584087165_780x439.jpg'/>
</div>

Please note that direct css code won't help. I need a way in javaScript to set the image's width using percentage but also basing on both the image's width size and the parent width size too.

Am really out-of ideas, Any help appreciated.

Thanks

</div>

Answer 1

First select your image and after that you can set the width from js.

$('#parent > img').css('width', '90%');