左侧的无效分配，javascript
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Invalid assignment left-hand side, javascript
提问by Hrishikesh Choudhari
I am sure I am doing something silly here:
我确定我在这里做了一些愚蠢的事情：
var addhtml = '<div id="leftbio" class="left-float">'
+= '<div id="bioname">e["screen_name]</div>'
+= '<div id="biophoto"><img src="e["profile_image_url"]"/></div>'
+= '<div id="biodetails">e["description"]</div>'
+= '</div>'; // invalid assignment left-hand side
console.log(addhtml);
And Netbeans is telling me that invalid assignment left-hand sideerror.
Netbeans 告诉我那个invalid assignment left-hand side错误。
Whats wrong ?
怎么了 ？
回答by Nicola Peluchetti
You don't need +=to concatenate, you just need +
你不需要+=连接，你只需要+
This is ok
还行吧
var addhtml = '<div id="leftbio" class="left-float">'
+ '<div id="bioname">e["screen_name]</div>'
+ '<div id="biophoto"><img src="e["profile_image_url"]"/></div>'
+'<div id="biodetails">e["description"]</div>'
+ '</div>';
console.log(addhtml);
回答by T.J. Crowder
+=means "take the thing on the left, add this to it, and store the result in the thing on the left". The left-hand side of your +=is a literal (the first one is '<div id="leftbio" class="left-float">). You can't assign to literals.
+=意思是“拿左边的东西，把它加进去，然后把结果存储在左边的东西里”。您的左侧+=是文字（第一个是'<div id="leftbio" class="left-float">）。您不能分配给文字。
Put it another way, a += bbasically means a = a + b. You can see how that doesn't work if ais a literal rather than a variable.
换句话说，a += b基本上是指a = a + b。如果a是文字而不是变量，您可以看到它是如何不起作用的。
You just want +there:
你只想+在那里：
var addhtml = '<div id="leftbio" class="left-float">'
+ '<div id="bioname">e["screen_name]</div>'
+ '<div id="biophoto"><img src="e["profile_image_url"]"/></div>'
+ '<div id="biodetails">e["description"]</div>'
+ '</div>';
console.log(addhtml);
To give you an idea of the difference between +and +=:
为了让你们之间的差异的想法+和+=：
var a, b;
a = "foo";
b = a + "bar"; // Doesn't modify `a`
console.log(a); // "foo"
console.log(b); // "foobar"
vs.
对比
var a, b;
a = "foo";
b = a += "bar"; // Modifies `a` (assigning the result to `b` is unusual -- very -- but valid)
console.log(a); // "foobar" - note it's changed
console.log(b); // "foobar"
Off-topic:
题外话：
I'd also recommend indenting the subsequent lines of the assignment statement, but that's just style:
我还建议缩进赋值语句的后续行，但这只是样式：
var addhtml = '<div id="leftbio" class="left-float">'
+ '<div id="bioname">e["screen_name]</div>'
+ '<div id="biophoto"><img src="e["profile_image_url"]"/></div>'
+ '<div id="biodetails">e["description"]</div>'
+ '</div>';
console.log(addhtml);
回答by KooiInc
The assignment (=) is not necessary, you can just use +. There are two other ways to construct multiline strings:
赋值 (=) 不是必需的，您可以使用 +。还有另外两种构造多行字符串的方法：
// method 1: use continuation \
var addhtml = '\
<div id="leftbio" class="left-float"> \
<div id="bioname">e["screen_name]</div> \
<div id="biophoto"><img src="e["profile_image_url"]"/></div> \
<div id="biodetails">e["description"]</div> \
</div>';
//method 2: use an array and join the elements
var addhtml = [
'<div id="leftbio" class="left-float">',
' <div id="bioname">e["screen_name]</div>',
' <div id="biophoto"><img src="e["profile_image_url"]"/></div>',
' <div id="biodetails">e["description"]</div>',
'</div>'
].join('');
回答by paxdiablo
x += yis shorthand for x = x + ywhich is not what you want here.
x += y是简写，x = x + y这不是您在这里想要的。
Either use:
要么使用：
var addhtml = '<div id="leftbio" class="left-float">';
addhtml += '<div id="bioname">e["screen_name]</div>';
addhtml += '<div id="biophoto"><img src="e["profile_image_url"]"/></div>';
addhtml += '<div id="biodetails">e["description"]</div>';
addhtml += '</div>';
or:
或者：
var addhtml = '<div id="leftbio" class="left-float">'
+ '<div id="bioname">e["screen_name]</div>'
+ '<div id="biophoto"><img src="e["profile_image_url"]"/></div>'
+ '<div id="biodetails">e["description"]</div>'
+ '</div>';
回答by Muhammad Zeeshan
Don't need =
不需要=
var addhtml = '<div id="leftbio" class="left-float">'
+ '<div id="bioname">e["screen_name]</div>'
+ '<div id="biophoto"><img src="e["profile_image_url"]"/></div>'
+ '<div id="biodetails">e["description"]</div>'
+ '</div>'; // invalid assignment left-hand side
console.log(addhtml);
回答by Giann
You cannot chain attribution operators like +=.
您不能像+=.
var addhtml = '<div id="leftbio" class="left-float">'
+ '<div id="bioname">e["screen_name]</div>'
+ '<div id="biophoto"><img src="e["profile_image_url"]"/></div>'
+ '<div id="biodetails">e["description"]</div>'
+ '</div>'; // invalid assignment left-hand side
console.log(addhtml);
