javascript中的javascript不起作用

我的javascript中有这个，但是

文档中的javascript.getElementById

不起作用

document.getElementById('addcategory1').innerHTML += "<input type='text' class='input-short' name='newcategory[1]' value='New Category 2' onfocus='javascript: if(this.value == 'New Category 2'){ this.value = ''; }' onblur='javascript: if(this.value==''){this.value='New Category 2';}'/><br/><br/>";

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我相信这里有一个引用问题：

onfocus='javascript: if(this.value == 'New Category 2'){ this.value = ''; }' onblur='javascript: if(this.value==''){this.value='New Category 2';}'

您在单引号脚本中嵌套了单引号

尝试将其替换为：

onfocus='if(this.value == "New Category 2'){this.value = ""; }' onblur='if(this.value==""){this.value="New Category 2";}'

您更大的

innerHTML

代码将是：

document.getElementById('addcategory1').innerHTML += "<input type='text' class='input-short' name='newcategory[1]' value='New Category 2' onfocus='if(this.value == \"New Category 2\"){ this.value = \"\"; }' onblur='if(this.value==\"\"){this.value=\"New Category 2\";}'/><br/><br/>";

document.getElementById（'addcategory1'）.innerHTML+=“

”；

正确地转义引号。使用双引号将单引号括起来

onfocus="javascript: if(this.value == 'New Category 2'){ this.value = ''; }" onblur="javascript: if(this.value==''){this.value='New Category 2';}"

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你需要转义你的单引号。

onfocus="javascript: if(this.value == 'New Category 2'){ this.value = ''; }" onblur="javascript: if(this.value==''){this.value='New Category 2';}"