Question

有人可以帮我吗？我是javaScript的新手，无法使用onblur或onfocus功能。这是HTML代码和.JS代码的片段。我已经在结束的body标签下方和head标签的右侧调用了我的script.js，以确保不是这样的......

HTML 的

                <label for="name">Full Name</label>
                <input type="text" id="name" name="fullname" value="First Name" />

                <label for="phone">Phone Number</label>
                <input type="text" id="phone" name="phonenumber" />

的JavaScript

function prepareEventHandlers() {

var firstNameField = document.getElementById("name");
var phoneField = document.getELementsById("phone");

firstNameField.onfocus = function() {
    if (firstNameField.value = "First Name") {
        firstNameField.value = " ";
    }
    };


firstNameField.onblur = function() {
    if (firstNameField.value == " ") {
        firstNameField.value = "First Name";
    }
};
}


window.onload = function() {
    prepareEventHandlers();
}

Answer 1

有一个拼写错误：var phoneField = document.getELementsById（“phone”）;

Answer 2

function prepareEventHandlers() {

var firstNameField = document.getElementById("name");
var phoneField = document.getElementById("phone");

firstNameField.onfocus = function() {
    if (firstNameField.value == "First Name") {
        firstNameField.value = "";
    }
    };


firstNameField.onblur = function() {
    if (!firstNameField.value.length) {
        firstNameField.value = "First Name";
    }
};
}


window.onload = function() {
    prepareEventHandlers();
}

初学者帮助onllur进行焦点故障排除

2 个答案: