[英]How can i check if my DOM already contains an element by id?
我想知道是否可以檢查我的DOM是否包含元素ID。 實際上,我會動態加載我的模板(劍道模板)並將其附加到我的體內。
<body>
...
<script type="text/x-kendo-template" id="test-view">
...
</script>
</body>
目前,我的加載腳本是
//Creates a gloabl object called templateLoader with a single method "loadExtTemplate"
var templateLoader = (function ($, host) {
//Loads external templates from path and injects in to page DOM
return {
//Method: loadExtTemplate
//Params: (string) path: the relative path to a file that contains template definition(s)
loadExtTemplate: function (path) {
//Use jQuery Ajax to fetch the template file
var tmplLoader = $.get(path)
.success(function (result) {
//On success, Add templates to DOM (assumes file only has template definitions)
var regSplit = new RegExp("[/\]+", "g");
var pathTab = path.split(regSplit);
var templateName = pathTab[pathTab.length - 1];
var regReplace = new RegExp("[.]+", "g");
var templateName = templateName.replace(regReplace, "-");
var s = $("<script type=\"text/x-kendo-template\" id=\"" + templateName + "\">" + result + "</script>");
$("body").append(s);
})
.error(function (result) {
alert("Error Loading Templates -- TODO: Better Error Handling");
})
tmplLoader.complete(function () {
//Publish an event that indicates when a template is done loading
$(host).trigger("TEMPLATE_LOADED", [path]);
});
}
};
})(jQuery, document);
在加載模板之前,我需要檢查該模板是否已經加載。 我需要檢查是否存在具有id =“ test-view”的腳本。 我怎樣才能做到這一點?
var elementExists = (document.getElementById("elementId") !== null);
現在, elementExists
將包含一個布爾值,該布爾值告訴您該元素是否已經存在。
var element = $('#' + templateName)
if(!element.length) {
// create your template
}
我建議添加
if(document.getElementById(templateName)) return;
后
var templateName = templateName.replace(regReplace, "-");
因此,您的代碼變為:
.success(function (result) {
//On success, Add templates to DOM (assumes file only has template definitions)
var regSplit = new RegExp("[/\]+", "g");
var pathTab = path.split(regSplit);
var templateName = pathTab[pathTab.length - 1];
var regReplace = new RegExp("[.]+", "g");
var templateName = templateName.replace(regReplace, "-");
if(document.getElementById(templateName)) return;
var s = $("<script type=\"text/x-kendo-template\" id=\"" + templateName + "\">" + result + "</script>");
$("body").append(s);
})
您可以使用長度或大小來做到這一點:
例如,
$("#test-view").length //$("#test-view").size()
使用jQuery:
if ($("#test-view").length) {...}
純JavaScript:
if (document.querySelectorAll("#test-view").length) {...}
和一些評論:
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