jquery - DIV height can't be resized with JavaScript -

i want resize height of div element javascript.

from div, i'm reading height

<div class="pages" id="alles"> 

this div i'l want resize (this can more one)

<div class="content-block" name="maxhoehe"> 

this javascript code:

var sh = document.getelementbyid("alles").offsetheight;          document.getelementsbyname("maxhoehe").style.height = sh-180 + "px"; 

in chrome, i'l following error:

uncaught typeerror: cannot set property 'height' of undefined 

i don't no why?

the document#getelementsbyname method returns collection of elements need first element index otherwise style property undefined( nodelist doesn't have style property ).

document.getelementsbyname("maxhoehe")[0].style.height = (sh - 180) + "px"; 

---

to update all, iterate on elements , update property.

var elements = document.getelementsbyname("maxhoehe");  // in latest browser use array.from(elements) [].slice.call(elements).foreach(function(ele){    ele.style.height = (sh - 180) + "px" });