var test = "      ";
//為空或全部為空格
if (test.match(/^[ ]*$/)) {
        console.log("all space or empty");
}

var test = "   \n   ";
//var test = "      ";
if(test.match(/^\s+$/)){
    console.log("all space or \\n")
}
if(test.match(/^[ ]+$/)){
    console.log("all space")
}
if(test.match(/^[ ]*$/)){
    console.log(
 
"all space or empty")
}
//空|空格|換行
if(test.match(/^\s*$/)){
    console.log("all space or \\n or empty")
}

JS判斷字符串是否為空或是否全為空格