css - Get button element and Style button using JavaScript -

<input type="submit" name="$submit$0" value="log in"> 

how element id/tag/class above type of button? want style too.

is correct?

if (document.getelementsbyclassname("submit") !== undefined || document.getelementsbyclassname("submit") !== null) {     var ele = document.getelementsbyclassname("submit");     (i = 0; < ele.length; i++) {         ele[i].style.color = "#6699ff";         ele[i].style.padding = "0px";         ele[i].style.height = "10px";         ele[i].style.width = "30px";     } } 

or?

if (document.getelementsbytagname("submit") !== undefined || document.getelementsbytagname("submit") !== null) {     var ele = document.getelementsbytagname("submit")[0];     ele.style.color = "#6699ff";     ele.style.padding = "0px";     ele.style.height = "10px";     ele.style.width = "30px"; } 

getelementbyid won't work here. in advance!

methods document.getelementsbyclassname document.getelementsbytagname never return undefined or null. result returned htmlcollection should check if collection empty or not. use length property:

if (document.getelementsbyclassname("submit").length) {     // ... } 

note in case, should checking type attribute of button, not it's class or tag name.

for method convenient document.queryselectorall (collection):

if (document.queryselectorall('[type=submit]').length) {}  

or if want check 1 button use document.queryselector (single element):

if (document.queryselector('[type=submit]')) {}