原生js實作尋找/新增/刪除/指定元素的class_javascript技巧

複製程式碼 程式碼如下:

window.onload = function(){
var gaga = document .getElementById( "gaga" );
addClass( gaga,"gaga1" )
addClass( gaga,"gaxx" );
removeClass( gaga,"gaga1" )
removeClass( gaga," gaga" )
function hasClass( elements,cName ){
return !!elements.className.match( new RegExp( "(\s|^)" cName "(\s|$)") ); / / ( \s|^ ) 判斷前面是否有空格（s | $ ）判斷後面是否有空格兩個感嘆號為轉換為布林值以方便做判斷
};
function addClass( elements,cName ){
if( !hasClass( elements,cName ) ){
elements.className = " " cName;
};
};
function removeClass( elements,cName ){
if ( hasClass( elements,cName ) ){
elements.className = elements.className.replace( new RegExp( "(\s|^)" cName "(\s|$)" )," " ); // replace方法是替換
};
};
};